Composition and method for treating neurological disease

ABSTRACT

The present disclosure is directed to methods of treating neurological disorders in a patient such as Parkinson&#39;s disease, drug-induced extrapyramidal reactions, and/or levodopa-induced dyskinesia comprising administering to the patient once daily in the morning a pharmaceutical composition comprising about 50 mg to about 400 mg of extended-release amantadine or a pharmaceutically acceptable salt thereof.

FIELD OF THE INVENTION

This invention relates to compositions and methods for treatingneurological disorders, such as Parkinson's disease, drug-inducedextrapyramidal reactions, and levodopa-induced dyskinesia.

BACKGROUND OF THE INVENTION

A neurological disorder is any disorder of the nervous system, which canbe categorized according to the primary location affected, the primarytype of dysfunction involved, or the primary type of cause. The broadestdivision is between central nervous system disorders and peripheralnervous system disorders. Movement disorder is one of the sub-categoriesthat involves the disorder of the central and/or peripheral nervoussystem such as Parkinson's disease, secondary Parkinsonism, essentialtremor, amyotrophic lateral sclerosis, Tourette's Syndrome, multiplesclerosis, extrapyramidal movement disorders, and various types ofPeripheral Neuropathy.

Among the various neurological disorders, Parkinson's Disease (PD) is aprogressive, chronic, neurodegenerative disease characterized byimpairment or death of neurons in the substantia nigra pars compacta.This neuronal deficit leads to motor symptoms including muscle rigidity,postural instability, tremor, akinesia or bradykinesia. In addition tothe motor symptoms, most patients develop other health problems relatedto PD. These symptoms are diverse but are collectively known asnon-motor symptoms and can likewise be troublesome and disabling. Theaverage age of onset of PD is approximately 60 years. Parkinson'sdisease is the second most common neurodegenerative disease afterAlzheimer's disease with an incidence of up to 1/1,000 person-years. Theprevalence of PD in the United States (US) is 0.3%, which increases to4-5% among people aged 85 years. Approximately 1,000,000 people in theUS have PD. Levodopa is the most common drug prescribed to relieve thesymptoms of PD. However, it is associated with motor and psychiatricside-effects. Consequently, interest has turned to alternative drugswith improved side-effect profiles to replace or augment levodopa.Amantadine, originally used as an antiviral drug, has been shown toimprove the symptoms of PD.

Levodopa-induced dyskinesia is a form of dyskinesia associated withlevodopa, used to treat Parkinson's disease. It often involveshyperkinetic movements, including chorea, dystonia, and athetosis. Inthe context of PD, dyskinesia is often the result of long-term dopaminetherapy. These motor fluctuations occur in up to 80% of PD patientsafter 5-10 years of levodopa treatment, with the percentage of affectedpatients increasing over time. Amantadine has also been shown to improvelevodopa-induced dyskinesia.

Drug-induced extrapyramidal reactions, also referred to as drug-inducedextrapyramidal symptoms or drug-induced extrapyramidal side effects, aredrug-induced movement disorders that include acute and tardive symptoms.These symptoms include dystonia (continuous spasms and musclecontractions), akathisia (motor restlessness), parkinsonism(characteristic symptoms such as rigidity), bradykinesia (slowness ofmovement), tremor, and tardive dyskinesia (irregular, jerky movements).Several types of drugs may cause drug-induced extrapyramidal reactions,such as antipsychotics, neuroleptic agents, antiemetics, andantidepressants. Levodopa has been previously tested for use in thetreatment of drug-induced extrapyramidal syndrome but with adisappointing therapeutic response.

Amantadine hydrochloride, a noncompetitive NMDA receptor antagonist, iscurrently approved both as an immediate release product and as anextended release product in the US. The first New Drug Application foramantadine in the US was approved 40 years ago, with an indication foridiopathic PD and other forms of symptomatic parkinsonism. Amantadinehas been shown in clinical studies to be an effective treatment toreduce motor fluctuations in patients with advanced PD. Amantadine hasalso been effective in treating drug-induced extrapyramidal reactionscaused by administration of, for example, antipsychotics or drugs toslow the progression of PD. However, treatment with amantadine haspreviously been only with immediate release (“IR”) amantadine astablets, capsules or oral liquid or syrup. Administration of the IR formraised issues with patient compliance, because of the number of dosagesrequired per day, and the negative side effects from use of the IRdosage form throughout the day.

To address the ongoing challenge of balancing the efficacies with therelative risk of adverse events, the inventors have developed a novelextended-release (ER) dosage form of amantadine. The extended-releasedosage form and once daily morning dosing schedule were developed toprovide more consistent levels of amantadine throughout the day and toenhance patient compliance by reducing administration from two or moretimes a day to once daily in the morning.

BRIEF SUMMARY OF THE INVENTION

The present disclosure provides a method of treating a patient withParkinson's disease, the method comprising administering to the patienta pharmaceutical composition comprising amantadine, or apharmaceutically acceptable salt thereof, in an extended release form,and amantadine, or a pharmaceutically acceptable salt thereof, in animmediate release form. In some embodiments, the patient is an adult.

The present disclosure also provides a method of treating drug-inducedextrapyramidal reactions in a patient, the method comprisingadministering to the patient a pharmaceutical composition comprisingamantadine, or a pharmaceutically acceptable salt thereof, in anextended release form, and amantadine, or a pharmaceutically acceptablesalt thereof, in an immediate release form. In some embodiments, thepatient is an adult.

The present disclosure also provides a method of treatinglevodopa-induced dyskinesia in a patient, the method comprisingadministering to the patient a pharmaceutical composition comprisingamantadine, or a pharmaceutically acceptable salt thereof, in anextended release form, and amantadine, or a pharmaceutically acceptablesalt thereof, in an immediate release form. In some embodiments, thepatient is an adult.

The present disclosure also provides a method of treating one or more ofParkinson's disease, drug-induced extrapyramidal reactions, andlevodopa-induced dyskinesia in a patient, the method comprisingadministering to the patient a pharmaceutical composition comprisingamantadine, or a pharmaceutically acceptable salt thereof, in anextended release form, and amantadine, or a pharmaceutically acceptablesalt thereof, in an immediate release form. In some embodiments, thepatient is an adult.

In some embodiments, the pharmaceutical composition comprises about 50mg to about 400 mg of amantadine or a pharmaceutically acceptable saltthereof. In some embodiments, the amantadine or a pharmaceuticallyacceptable salt thereof in an extended release form is from about 70 mgto about 300 mg. In some embodiments, the amantadine or apharmaceutically acceptable salt thereof in an immediate release form isfrom about 40 mg to about 70 mg.

In some embodiments, at least about 50% of amantadine or apharmaceutically acceptable salt thereof is in an extended release form.In one embodiment, between about 60% and about 82% of amantadine or apharmaceutically acceptable salt thereof is in an extended release form.

In some embodiments, the composition is administered once daily in themorning.

In some embodiments, the pharmaceutical composition comprises about 129mg to about 258 mg of amantadine free base equivalent.

In some embodiments, the pharmaceutical composition is a dosage formcomprising 129 mg, 193 mg, or 258 mg of amantadine free base equivalent.

In some embodiments, the pharmaceutical composition is a dosage formcomprising about 48 mg of amantadine free base equivalent, in animmediate release form.

In some embodiments, the pharmaceutically acceptable salt thereof isamantadine HCl.

In some embodiments, the pharmaceutical composition is a dosage formcomprising 160 mg, 240 mg, or 320 mg of amantadine HCl.

In some embodiments, the dC/dT values of the pharmaceutical compositionof the invention and the immediate release form are measured in the samepharmacokinetic study.

In some embodiments, the method comprises: i) administering to thepatient a pharmaceutical composition comprising about 160 mg ofamantadine or a pharmaceutically acceptable salt thereof for at leastone week; and ii) increasing the dose of amantadine or apharmaceutically acceptable salt thereof to a maximum daily dose ofabout 320 mg. In some embodiments, the dose is increased to about 240 mgof amantadine or a pharmaceutically acceptable salt thereof. In someembodiments, the dose increase is weekly. In one embodiment, each of thepharmaceutical compositions comprises an extended release componentcomprising amantadine or a pharmaceutically acceptable salt thereof; andan immediate release component comprising about 60 mg amantadine or apharmaceutically acceptable salt thereof.

In some embodiments, the method comprises: i) administering to thepatient a pharmaceutical composition comprising about 129 mg ofamantadine free base equivalent for at least one week; and ii)increasing the dose of amantadine free base equivalent to a maximumdaily dose of about 322 mg. In one embodiment, the maximum daily dose ofabout 322 mg comprises a pharmaceutical composition comprising about 129mg of amantadine free base equivalent and a pharmaceutical compositioncomprising about 193 mg of amantadine free base equivalent. In someembodiments, the dose is increased to about 193 mg of amantadine freebase equivalent. In some embodiments, the dose increase is weekly. Inone embodiment, each of the pharmaceutical compositions comprises anextended release component comprising amantadine or a pharmaceuticallyacceptable salt thereof; and an immediate release component comprisingabout 48 mg amantadine free base equivalent.

In some embodiments, the method comprises: i) administering to thepatient a pharmaceutical composition comprising about 129 mg ofamantadine free base equivalent for at least one week; ii) increasingthe dose of amantadine by administering to the patient a pharmaceuticalcomposition comprising about 193 mg of amantadine free base equivalent.In some embodiments, each of the pharmaceutical compositions comprisesan extended release component comprising amantadine free baseequivalent; and an immediate release component comprising about 48 mg ofamantadine free base equivalent. In some embodiments, the pharmaceuticalcomposition is administered once daily in the morning.

In some embodiments, the method comprises: i) administering to thepatient a pharmaceutical composition consisting essentially of about 129mg of amantadine free base equivalent for at least one week; ii)increasing the dose of amantadine by administering to the patient apharmaceutical composition consisting essentially of about 193 mg ofamantadine free base equivalent. In some embodiments, each of thepharmaceutical compositions consists of an extended release componentconsisting essentially of amantadine free base equivalent and animmediate release component consisting essentially of about 48 mg ofamantadine free base equivalent. In some embodiments, the pharmaceuticalcomposition is administered once daily in the morning.

In some embodiments, the method comprises: i) administering to thepatient a pharmaceutical composition comprising about 129 mg ofamantadine free base equivalent for at least one week; ii) increasingthe dose of amantadine by administering to the patient a pharmaceuticalcomposition comprising about 193 mg of amantadine free base equivalentfor at least one week; iii) increasing the dose of amantadine byadministering to the patient a pharmaceutical composition comprisingabout 258 mg of amantadine free base equivalent.

In some embodiments, each of the pharmaceutical compositions comprisesi) an extended release component comprising amantadine free baseequivalent; and ii) an immediate release component comprising about 48mg of amantadine free base equivalent. In some embodiments, thepharmaceutical compositions are administered once daily in the morning.In some embodiments, the method further comprises: iv) decreasing thedose of amantadine by administering to the patient a pharmaceuticalcomposition comprising about 193 mg of amantadine free base equivalentfor at least one week; and v) decreasing the dose of amantadine byadministering to the patient a pharmaceutical composition comprisingabout 129 mg of amantadine free base equivalent for at least one week.

In some embodiments, the pharmaceutical composition provides a meanchange in amantadine plasma concentration as a function of time (dC/dT)that is between about 40% and about 70% of the dC/dT provided by thesame quantity of amantadine or a pharmaceutically acceptable saltthereof in an immediate release form, wherein the dC/dT values aremeasured in a single dose human pharmacokinetic study over the timeperiod between 0 and 4 hours after administration.

In some embodiments, the T_(max) of the pharmaceutical composition aftera single-dose administration is between about 5 and about 12 hours.

In some embodiments, the median T_(max) of the pharmaceuticalcomposition after a single-dose administration is about 7.5 hours.

In some embodiments, the mean C_(max) of the pharmaceutical compositionafter a single-dose administration is between about 540 and about 895ng/ml.

In some embodiments, the mean C_(max) of the pharmaceutical compositionafter a single-dose administration is between about 370 and about 550ng/ml.

In some embodiments, the mean C_(max) of the pharmaceutical compositionafter a single-dose administration is between about 265 and about 390ng/ml.

In some embodiments, the mean AUC_(0-∞) of the pharmaceuticalcomposition after a single-dose administration is between about 12,000and about 26,000 ng·h/mL.

In some embodiments, the mean AUC_(0-∞) of the pharmaceuticalcomposition after a single-dose administration is between about 8,000and about 20,000 ng·h/mL.

In some embodiments, the mean AUC_(0-∞) of the pharmaceuticalcomposition after a single-dose administration is between about 6,000and about 12,000 ng·h/mL.

In some embodiments, the mean AUC_(0-∞) of the pharmaceuticalcomposition after a single-dose administration is between about 6,900and about 11,000 ng·h/mL.

In some embodiments, the mean AUC_(0-∞) of the pharmaceuticalcomposition after a single-dose administration is between about 10,000and about 40,000 ng·h/mL.

In some embodiments, the pharmaceutical composition has an in vitrodissolution profile ranging between about 0.1% to about 50% in about 0.5hour, about 20% to about 80% in about 2.5 hours, about 40% to about 90%in about 4 hours, and no less than about 85% in about 8 hours asmeasured in water using a USP type II (paddle) dissolution system at 50rpm, at a temperature of 37±0.5 C.

In one embodiment, the pharmaceutical composition has an in vitrodissolution profile ranging between about 28% to about 48% in about 0.5hour, about 39% to about 63% in about 2.5 hours, about 61% to about 85%in about 4 hours, and no less than about 85% in about 8 hours asmeasured in water using a USP type II (paddle) dissolution system at 50rpm, at a temperature of 37±0.5 C.

In another embodiment, the pharmaceutical composition has an in vitrodissolution profile ranging between about 15% to about 35% in about 0.5hour, about 29% to about 53% in about 2.5 hours, about 53% to about 77%in about 4 hours, and no less than about 85% in about 8 hours asmeasured in water using a USP type II (paddle) dissolution system at 50rpm, at a temperature of 37+0.5 C.

In yet another embodiment, the pharmaceutical composition has an invitro dissolution profile ranging between about 9% to about 29% in about0.5 hour, about 37% to about 62% in about 2.5 hours, about 59% to about83% in about 4 hours, and no less than about 85% in about 8 hours asmeasured in water using a USP type II (paddle) dissolution system at 50rpm, at a temperature of 37±0.5 C.

In some embodiments, the drug-induced extrapyramidal reaction isselected from the group consisting of dystonia, akathisia, parkinsonism,bradykinesia, tremor, and tardive dyskinesia, or any combinationthereof.

In some embodiments, the drug-induced extrapyramidal reaction is causedby an antipsychotic, antiemetic, antidepressant, or any combinationthereof. In one embodiment, the antipsychotic comprises haloperidol,fluphenazine, thilthixene, trifluoroperazine, acetophenazine,prochlorperazine, perphenazine, loxapine, chlorpromazine,triflupromazine, molindone, mesoridazine, chlorprothixene, thioridazine,clozapine or any combinations thereof. In one embodiment, the antiemeticcomprises metoclopramide, trimethobenzamide or a combination thereof. Inone embodiment, the antidepressant comprises selective serotoninreuptake inhibitors (SSRI), serotonin-norepinephrine reuptake inhibitors(SNRI), norepinephrine-dopamine reuptake inhibitors (NDRI) or anycombination thereof.

In some embodiments, the patient continues to receive the antipsychotic,antiemetic, antidepressant, or any combination thereof.

In some embodiments, the method improves dyskinesia in a patient withlevodopa-induced dyskinesia (LID) as determined by a reduction in atotal Unified Dyskinesia Rating Scale (UdysRS) score after twelve weeks.

In some embodiments, the reduction in UdysRS score is between about −2and about −7 after twelve weeks, compared to placebo.

In some embodiments, the reduction in UdysRS score is about −5 aftertwelve weeks, compared to placebo.

In some embodiments, the reduction in UdysRS score is between about −9and about −17 after twelve weeks.

In some embodiments, the reduction in UdysRS score is about −13 aftertwelve weeks.

In some embodiments, the method increases the number of awake ON hourswithout dyskinesia in the patient.

In some embodiments, the method increases the number of awake ON hourswithout dyskinesia in the patient by about 1 to about 4 hours aftertwelve weeks.

In some embodiments, the method increases the number of awake ON hourswithout dyskinesia in the patient by about 4 hours after twelve weeks.

In some embodiments, the number of awake ON hours without dyskinesia inthe patient is between about 9 and about 14 hours.

In some embodiments, the methods do not worsen Parkinson's diseasesymptoms in the patient.

In some embodiments, the methods do not worsen drug-inducedextrapyramidal symptoms in the patient.

In some embodiments, the methods do not worsen levodopa-induceddyskinesia in the patient.

In some embodiments, the relative bioavailability of amantadine or apharmaceutically acceptable salt thereof is approximately the same underfed and fasting conditions.

In some embodiments, the pharmaceutical composition is an osmoticdevice. In one embodiment, the osmotic devise comprises a semipermeablemembrane.

In some embodiments, the osmotic device comprises: i) an extendedrelease component comprising about 70 mg to about 300 mg of amantadineor a pharmaceutically acceptable salt thereof; and ii) an immediaterelease component comprising about 40 to about 70 mg of amantadine or apharmaceutically acceptable salt thereof. In one embodiment, thepharmaceutical composition provides a mean change in amantadine plasmaconcentration as a function of time (dC/dT) that is between about 40%and about 70% of the dC/dT provided by the same quantity of amantadineor a pharmaceutically acceptable salt thereof in an immediate releaseform, wherein the dC/dT values are measured in a single dose humanpharmacokinetic study over the time period between 0 and 4 hours afteradministration.

In some embodiments, the pharmaceutical composition is administered as acombination with a second agent. In some embodiments, the second agentfurther comprises one or more compounds selected from the groupconsisting of aromatic-L-amino-acid decarboxylase inhibitors, dopamineagonists, COMT (catechol O-methyltransferase) inhibitors, MAO-B(monoamine oxidase B) inhibitors, anticholinergics, benzodiazepines,SSRIs (selective serotonin reuptake inhibitors), tricyclic andtetracyclic antidepressants, nonsteroidal anti-inflammatory agents,non-narcotic analgesic, narcotic analgesics, ADORA2A (adenosine A2Areceptor) antagonists, anti-epileptic agents, and any combinationsthereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts the amantadine plasma concentration-time (mean) profilefollowing oral administration of one 320-mg Amantadine HCl ER Tabletunder fasting (T1) or fed (T2) condition. Study III.

FIG. 2 depicts the mean amantadine plasma concentration-time profilefollowing oral administration of one 160 mg (Treatment-A), 240 mg(Treatment-B) or 320 mg (Treatment-C) Amantadine HCl ER Tablet or 160 mgof Amantadine HCl Oral Syrup (Treatment-D) to 23 fasted healthyvolunteers, Study II.

FIG. 3 depicts the amantadine plasma concentration-time (mean) profilefollowing oral administration of one 320-mg Amantadine HCl ER Tabletdaily (Treatment-A) or 160 mg of Amantadine HCl Oral Syrup, 50 mg/5 mLtwice daily (Treatment-B) for 7 days to fasted healthy volunteers, StudyI.

FIG. 4 depicts the amantadine plasma concentration-time (mean) profile(semi-logarithmic scale) following oral administration of one 320-mgAmantadine HCL ER Tablet daily (Treatment-A) or 160 mg of Amantadine HClOral Syrup, 50 mg/5 mL twice daily (Treatment-B) for 7 days to fastedhealthy volunteers, Study I.

FIG. 5 depicts the dissolution profile of Amantadine HCl ER Tablets, 160mg in various dissolution media.

FIG. 6 depicts the dissolution profile of Amantadine HCl ER Tablets, 240mg in various dissolution media.

FIG. 7 depicts the dissolution profile of Amantadine HCl ER Tablets, 320mg in various dissolution media.

FIG. 8 depicts alcohol effect on the dissolution profile of AmantadineHCl ER 160-mg Tablets in 0.1 N HCl.

FIG. 9 depicts alcohol effect on the dissolution profile of AmantadineHCl ER 160-mg Tablets in water.

FIG. 10 depicts alcohol effect on the dissolution profile of AmantadineHCl ER 160-mg Tablets (0.1 N HCl media) over two-hour and eight-hourperiods.

FIG. 11 depicts alcohol effect on the dissolution profile of AmantadineHCl ER 160-mg Tablets in water media over two-hour and eight-hourperiods.

FIG. 12 depicts alcohol effect on the dissolution profile of AmantadineHCl ER 240-mg Tablets in 0.1 N HCl.

FIG. 13 depicts alcohol effect on the dissolution profile of AmantadineHCl ER 240-mg Tablets in water.

FIG. 14 depicts alcohol effect on the dissolution profile of AmantadineHCl ER 320-mg Tablets in 0.1 N HCl.

FIG. 15 depicts alcohol effect on the dissolution profile of AmantadineHCl ER 320-mg Tablets in water.

FIG. 16 depicts the individual and mean amantadine plasma concentration24 hours after dose 5, 6 and 7 of Amantadine HCl ER Tablets, 320 mg.Study I.

FIG. 17 depicts the simulated amantadine plasma concentration-timeprofiles over a period of 24 hours following administration of 200 mgamantadine in an immediate release formulation twice a day (TMT 3) and400 mg amantadine ((160 mg tablet+240 tablet administeredsimultaneously) in a sustained release formulation once a day (TMT 10).

DETAILED DESCRIPTION OF THE INVENTION Definitions

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this disclosure belongs. In case of conflict, thepresent application including the definitions will control. Unlessotherwise required by context, singular terms shall include pluralitiesand plural terms shall include the singular. All publications, patentsand other references mentioned herein are incorporated by reference intheir entireties for all purposes as if each individual publication orpatent application were specifically and individually indicated to beincorporated by reference.

Although methods and materials similar or equivalent to those describedherein can be used in practice or testing of the present disclosure,suitable methods and materials are described below. The materials,methods and examples are illustrative only and are not intended to belimiting. Other features and advantages of the disclosure will beapparent from the detailed description and from the claims.

In order to further define this disclosure, the following terms anddefinitions are provided.

The singular forms “a,” “an” and “the” include plural referents unlessthe context clearly dictates otherwise. The terms “a” (or “an”), as wellas the terms “one or more,” and “at least one” can be usedinterchangeably herein. In certain aspects, the term “a” or “an” means“single.” In other aspects, the term “a” or “an” includes “two or more”or “multiple.”

The term “about” is used herein to mean approximately, roughly, around,or in the regions of. When the term “about” is used in conjunction witha numerical range, it modifies that range by extending the boundariesabove and below the numerical values set forth. In general, the term“about” is used herein to modify a numerical value above and below thestated value by a variance of 10 percent, up or down (higher or lower).

The term “and/or” where used herein is to be taken as specificdisclosure of each of the two specified features or components with orwithout the other. Thus, the term “and/or” as used in a phrase such as“A and/or B” herein is intended to include “A and B,” “A or B,” “A”(alone), and “B” (alone). Likewise, the term “and/or” as used in aphrase such as “A, B, and/or C” is intended to encompass each of thefollowing aspects: A, B, and C; A, B, or C; A or C; A or B; B or C; Aand C; A and B; B and C; A (alone); B (alone); and C (alone).

The term “immediate release” or “IR” as used herein means a release ofan active agent to an environment over a period of seconds to no morethan about 30 minutes once release has begun and release begins within asecond to no more than about 15 minutes after administration.

The term “rapid release” as used herein means a release of an activeagent to an environment over a period of 1 minute to one hour oncerelease has begun and release can begin within a few minutes afteradministration or after expiration of a delay period (lag time) afteradministration.

The term “controlled release” as used herein means a release of anactive agent to an environment over a period of about eight hours up toabout 12 hours, 16 hours, 18 hours, 20 hours, a day, or more than a day.A controlled release can begin within a few minutes after administrationor after expiration of a delay period (lag time) after administration.

The term “sustained release” as used herein means a controlled releaseof an active agent to maintain a constant drug level in the blood ortarget tissue of a subject to which the device is administered.

The term “extended release” or “ER” as used herein means a controlledrelease of an active agent from a dosage form to an environment over anextended period of time. As used herein, the term “extended release”profile assumes the definition as widely recognized in the art ofpharmaceutical sciences. An extended release dosage form will releasedrug at substantially constant rate over an extended period of time or asubstantially constant amount of drug will be released incrementallyover an extended period of time. The term “extended release”, as regardsto drug release, includes the terms “prolonged release”, “sustainedrelease”, or “slow release”, as these terms are used in thepharmaceutical sciences.

The term “amantadine” as used herein refers to the free base or apharmaceutically acceptable salt form of amantadine.

The term “free base” as used herein includes, but is not limited to, theunprotonated form of a therapeutic agent, molecule, or compound.Additionally, “free base” includes, but is not limited to, the neutralform of a molecule or compound.

The term “free base equivalent” as used herein refers to the salt formof a therapeutic agent, molecule, or compound that has the same molarquantity as its free base. For example, 60 mg amantadine HCl salt is 48mg amantadine free base equivalent. 160 mg amantadine HCl salt is 129 mgamantadine free base equivalent. 240 mg amantadine HCl salt is 193 mgamantadine free base equivalent. 320 mg amantadine HCl salt is 258 mgamantadine free base equivalent. All numbers are rounded up to thenearest integer.

The term “unitary core” as used herein means the core of an osmoticdevice that is not divided into two or more layers or laminas. The coreis considered to be the composition enclosed within the semipermeablemembrane of the osmotic device.

The term “pharmaceutically acceptable” as used herein refers to thosecompounds, materials, compositions, and/or dosage forms which are,within the scope of sound medical judgment, suitable for use in contactwith the tissues of human beings and animals without excessive toxicity,irritation, allergic response, or other problem or complication,commensurate with a reasonable benefit/risk ratio.

The term “effective amount” or “pharmaceutically effective amount” asused herein refers to the amount or quantity of a drug orpharmaceutically active substance which is sufficient to elicit therequired or desired therapeutic response, or in other words, the amountwhich is sufficient to elicit an appreciable biological response whenadministered to a patient.

The term “unit dosage form” or “unit dose composition” as used hereinrefers to a device containing a quantity of the therapeutic compound,said quantity being such that one or more predetermined units may beprovided as a single therapeutic administration.

The term “C_(max)” as used herein refers to the maximum plasmaconcentration of a drug after it is administered to a patient.

The term “T_(max)” as used herein refers to the time required to reachthe maximal plasma concentration (“C_(max)”) after administration of adrug.

The term “AUC” as used herein refers to the area under the curve of aplot of plasma concentration versus time following administration of adrug.

The term “AUC_(0-t)” as used herein refers to the area under the drugconcentration-time curve from time zero to the time of the lastmeasurable concentration (C₁).

The term “AUC_(0-∞)” as used herein refers to the area under the drugconcentration-time curve from time zero to infinity.

The term “dC/dT” as used herein refers to the change of plasmaconcentration of a drug over a prescribed time.

The term “steady state” as used herein means that the amount of the drugreaching the system is approximately the same as the amount of the drugleaving the system. Thus, at “steady-state,” the patient's bodyeliminates the drug at approximately the same rate that the drug becomesavailable to the patient's system through absorption into the bloodstream.

The term “LOCF” as used herein refers to last observation carriedforward.

The term “treating” or “treatment” as used herein refers to theadministration of a composition to a subject for therapeutic purposes.

The term “UDysRS” as used herein refers to the Unified DyskinesiaRatings Scale.

The term “awake ON hours” or “awake ‘ON’ hours”, as used herein, refersto time in which the medication has therapeutic benefits related tomobility, slowness and/or rigidity.

The term “awake OFF hours” or “awake ‘OFF’ hours” as used herein refersto time when a medication's therapeutic effect has diminished or stoppedand no longer provides a benefit related to mobility, slowness and/orstiffness.

The term “mean” refers to an average value in a patient population. Forexample, a “mean Cmax” refers to an average of the maximum plasmaconcentrations of a drug in a patient population.

The term “adult” refers to a person 18 years of age or older.

Methods of Treatment

The present invention relates to a method of treating Parkinson'sdisease, comprising administering to the patient a pharmaceuticalcomposition comprising 100 mg to 400 mg of amantadine or apharmaceutically acceptable salt thereof. In some embodiments, themethod comprises treating a patient with idiopathic Parkinson's disease,symptomatic parkinsonism, parkinsonism in association with cerebralarteriosclerosis, or any combination thereof.

The present invention also relates to a method of treating drug-inducedextrapyramidal reactions in a patient, comprising administering to thepatient a pharmaceutical composition comprising amantadine, or apharmaceutically acceptable salt thereof, in an extended release form,and amantadine, or a pharmaceutically acceptable salt thereof, in animmediate release form.

The drug-induced extrapyramidal reactions may be caused by the previousor concomitant administration of drugs such as one or moreantipsychotics, antidepressants, or other drugs to treat PD or symptomsof PD.

The present invention also relates to a method of treatinglevodopa-induced dyskinesia in a patient, comprising administering tothe patient a pharmaceutical composition comprising amantadine, or apharmaceutically acceptable salt thereof, in an extended release form,and amantadine, or a pharmaceutically acceptable salt thereof, in animmediate release form.

The present invention also relates to a method of treating one or moreof Parkinson's disease, drug-induced extrapyramidal reactions, andlevodopa-induced dyskinesia in a patient, comprising administering tothe patient a pharmaceutical composition comprising amantadine, or apharmaceutically acceptable salt thereof, in an extended release form,and amantadine, or a pharmaceutically acceptable salt thereof, in animmediate release form.

In some embodiments, the pharmaceutical composition is administereddaily or once daily in the morning. In some embodiments, thepharmaceutical composition is administered daily or once daily in theafternoon. In some embodiments, the pharmaceutical composition isadministered daily or once daily in the evening. In one embodiment, thepharmaceutical composition is administered more than 4 hours beforebedtime.

In some embodiments, the patient is an adult.

In some embodiments of the invention, a pharmaceutically acceptable saltof amantadine is an inorganic acid salt. In some embodiments, theinorganic salt of amantadine is a mineral acid salt. In someembodiments, the inorganic salt of amantadine is a hydrochloride, ahydrobromide, a hydroiodide, a nitrate, a sulfate, a bisulfate, or aphosphate salt of amantadine. In one embodiment, the amantadine salt isa hydrochloride salt.

Dosing

In some embodiments, the amount of amantadine administered per day isfrom about 50 mg to about 1000 mg, from about 50 mg to about 900 mg,from about 50 mg to about 800 mg, from about 50 mg to about 700 mg, fromabout 50 mg to about 600 mg, from about 50 mg to about 500 mg, fromabout 50 mg to about 400 mg, from about 50 mg to about 300 mg, fromabout 50 mg to about 200 mg, or from about 50 mg to about 100 mg.

In some embodiments, the amount of amantadine administered per day isfrom about 100 mg to about 1000 mg, from about 100 mg to about 900 mg,from about 100 mg to about 800 mg, from about 100 mg to about 700 mg,from about 100 mg to about 600 mg, from about 100 mg to about 500 mg,from about 100 mg to about 400 mg, from about 100 mg to about 300 mg, orfrom about 100 mg to about 200 mg. In one embodiment, the amount ofamantadine administered per day is from about 100 mg to about 400 mg. Inanother embodiment, the amount of amantadine administered per day isfrom about 160 mg to about 320 mg.

In some embodiments, the amount of amantadine free base equivalentadministered per day is from about 100 mg to about 1000 mg, from about100 mg to about 900 mg, from about 100 mg to about 800 mg, from about100 mg to about 700 mg, from about 100 mg to about 600 mg, from about100 mg to about 500 mg, from about 100 mg to about 400 mg, from about100 mg to about 300 mg, or from about 100 mg to about 200 mg. In oneembodiment, the amount of amantadine free base equivalent administeredper day is from about 120 mg to about 300 mg. In another embodiment, theamount of amantadine free base equivalent administered per day is fromabout 130 mg to about 250 mg. In some embodiments, the amount ofamantadine free base equivalent administered per day is from about 129mg to about 258 mg. In some embodiments, the amount of amantadine freebase equivalent administered per day is from 129 mg to 258 mg.

In some embodiments, the amount of amantadine administered per day isfrom about 100 mg to about 150 mg, from about 150 mg to about 200 mg,from about 200 mg to about 250 mg, from about 250 mg to about 300 mg,from about 300 mg to about 350 mg, from about 350 mg to about 400 mg. Inone embodiment, the amount of amantadine administered per day is about160 mg. In another embodiment, the amount of amantadine administered perday is about 240 mg. In another embodiment, the amount of amantadineadministered per day is about 320 mg. In another embodiment, the amountof amantadine administered per day is 160 mg. In another embodiment, theamount of amantadine administered per day is 240 mg. In yet anotherembodiment, the amount of amantadine administered per day is 320 mg. Inone embodiment, the amount of amantadine free base equivalentadministered is 129 mg or about 129 mg. In one embodiment, the amount ofamantadine free base equivalent administered per day is 129 mg or about129 mg. In another embodiment, the amount of amantadine free baseequivalent administered is 193 mg or about 193 mg. In anotherembodiment, the amount of amantadine free base equivalent administeredper day is 193 mg or about 193 mg. In yet another embodiment, the amountof amantadine free base equivalent administered is 258 mg or about 258mg. In yet another embodiment, the amount of amantadine free baseequivalent administered per day is 258 mg or about 258 mg.

In some embodiments, the pharmaceutical composition comprises anextended release component comprising amantadine or a pharmaceuticallyacceptable salt thereof and an immediate release component comprisingamantadine or a pharmaceutically acceptable salt thereof.

In some embodiments, the amount of amantadine in an extended releaseform administered per day is from about 50 mg to about 500 mg, fromabout 50 mg to about 400 mg, from about 50 mg to about 300 mg, fromabout 50 mg to about 200 mg, or from about 50 mg to about 100 mg.

In some embodiments, the amount of amantadine in the extended releaseform administered per day is from about 50 mg to about 500 mg, fromabout 50 mg to about 400 mg, from about 50 mg to about 300 mg, or fromabout 50 mg to about 200 mg. In one embodiment, the amount of amantadinein the extended release form administered per day is from about 70 mg toabout 300 mg.

In some embodiments, the amount of amantadine in the extended releaseform administered per day is from about 50 mg to about 100 mg, fromabout 100 mg to about 150 mg, from about 150 mg to about 200 mg, fromabout 200 mg to about 250 mg, or from about 250 mg to about 300 mg. Inone embodiment, the amount of amantadine in the extended release formadministered per day is about 100 mg. In another embodiment, the amountof amantadine in the extended release form administered per day is about180 mg. In another embodiment, the amount of amantadine in the extendedrelease form administered per day is about 260 mg. In one embodiment,the amount of amantadine in the extended release form administered perday is about 81 mg of amantadine free base equivalent. In anotherembodiment, the amount of amantadine in the extended release formadministered per day is about 145 mg of amantadine free base equivalent.In another embodiment, the amount of amantadine in the extended releaseform administered form per day is about 210 mg of amantadine free baseequivalent.

In some embodiments, the amount of amantadine in the immediate releaseform administered per day is from about 20 mg to about 100 mg, fromabout 20 mg to about 90 mg, from about 20 mg to about 80 mg, from about20 mg to about 70 mg, from about 20 mg to about 60 mg, from about 20 mgto about 50 mg, from about 20 mg to about 40 mg, or from about 20 mg toabout 30 mg.

In some embodiments, the amount of amantadine in the immediate releaseform administered per day is from about 40 mg to about 100 mg, fromabout 40 mg to about 90 mg, from about 40 mg to about 80 mg, from about40 mg to about 70 mg, or from about 40 mg to about 60 mg. In oneembodiment, the amount of amantadine in the immediate release formadministered per day is from about 40 mg to about 70 mg.

In some embodiments, the amount of amantadine in the immediate releaseform administered per day is from about 10 mg to about 20 mg, from about20 mg to about 30 mg, from about 30 mg to about 40 mg, from about 40 mgto about 50 mg, from about 50 mg to about 60 mg, from about 60 mg toabout 70 mg, from about 70 mg to about 80 mg, from about 80 mg to about90 mg, or from about 90 mg to about 100 mg. In one embodiment, theamount of amantadine in the immediate release form administered per dayis about 60 mg. In one embodiment, the amount of amantadine in theimmediate release form administered per day is about 48 mg of amantadinefree base equivalent.

In some embodiments, the amantadine administered is amantadine HCl. Inone embodiment, the amount of amantadine HCl administered per day isabout 160 mg, wherein the 160 mg amantadine HCl comprises about 100 mgamantadine HCl in the extended release form and about 60 mg amantadineHCl in the immediate release form. In another embodiment, the amount ofamantadine HCl administered per day is about 240 mg, wherein the 240 mgamantadine HCl comprises about 180 mg amantadine HCl in the extendedrelease form and about 60 mg amantadine HCl in the immediate releaseform. In another embodiment, the amount of amantadine HCl administeredper day is about 320 mg, wherein the about 320 mg amantadine HClcomprises about 260 mg amantadine HCl in the extended release form andabout 60 mg amantadine HCl in the immediate release form.

In some embodiments, the pharmaceutical composition is a dosage formcomprising from about 100 mg to about 300 mg of amantadine free baseequivalent. In one embodiment, the pharmaceutical composition is adosage form comprising about 129 mg of amantadine free base equivalent(which equals about 160 mg of amantadine HCl). In another embodiment,the pharmaceutical composition is a dosage form comprising about 193 mgof amantadine free base equivalent (which equals about 240 mg ofamantadine HCl). In one embodiment, the pharmaceutical composition is adosage form comprising about 258 mg of amantadine free base equivalent(which equals about 320 mg of amantadine HCl).

In one embodiment, the pharmaceutical composition is a dosage formcomprising about 81 mg of amantadine free base equivalent in extendedrelease form and about 48 mg of amantadine free base equivalent inimmediate release form. In another embodiment, the pharmaceuticalcomposition is a dosage form comprising about 145 mg of amantadine freebase equivalent in extended release form and about 48 mg of amantadinefree base equivalent in immediate release form. In yet anotherembodiment, the pharmaceutical composition is a dosage form comprisingabout 210 mg of amantadine free base equivalent in extended release formand about 48 mg of amantadine free base equivalent in immediate releaseform.

Dosing Frequency and Dose Escalation

According to the present invention, a subject (e.g., human) having or atrisk of having PD, is administered any of the pharmaceuticalcompositions described herein. In addition, according to the presentinvention, a subject (e.g., human) having or at risk of having adrug-induced extrapyramidal reaction, is administered any of thepharmaceutical compositions described herein.

In addition, according to the present invention, a subject (e.g., human)having or at risk of having levodopa-induced dyskinesia, is administeredany of the pharmaceutical compositions described herein.

In some embodiments, the pharmaceutical compositions are administered ata constant, therapeutically-effective dose from the onset of therapy.For example, a pharmaceutical composition containing an extended releasecomponent and an immediate release component of amantadine may beadministered three times per day, twice per day, or once per day in aunit dose comprising a total daily amantadine dose of about 50 mg, about100 mg, about 200 mg, about 300 mg, about 400 mg, about 500 mg, about600 mg, about 700 mg, or about 800 mg. In one embodiment, thepharmaceutical composition is administered once daily. In oneembodiment, the pharmaceutical composition is administered in themorning. In one embodiment, the pharmaceutical composition isadministered in the afternoon. In one embodiment, the pharmaceuticalcomposition is administered in the evening. In one embodiment, thepharmaceutical composition is administered more than 4 hours beforebedtime. In some embodiments, a pharmaceutical composition containing anextended release component and an immediate release component ofamantadine HCl may be administered twice per day or once per day in aunit dose comprising a total daily amantadine dose, or pharmaceuticallyacceptable salt thereof, of about 160 mg, about 240 mg, or about 320 mg.

In some embodiments, the pharmaceutical compositions are administered ina dose-escalating fashion. In some embodiments, the method of treatmentcomprises a Titration Period (the initial dose), a Maintenance Period,and/or a Taper Period.

In some embodiments, the Titration Period is in weekly intervals, fromabout one week to about four weeks, from about one week to about threeweeks, from about one week to about two weeks, from about two weeks toabout four weeks, from about two weeks to about three weeks, or fromabout three weeks to about four weeks. In some embodiments, theTitration Period is about one week, about two weeks, about three weeks,or about four weeks. In one embodiment, the Titration Period is aboutone week. In another embodiment, the Titration Period is about twoweeks. In one embodiment, the Titration Period is one week. In anotherembodiment, the Titration Period is two weeks. In one embodiment, thepatient is observed for the occurrence of hallucinations throughouttreatment, especially at initiation and after dose increases. In someembodiments, the treatment should not be discontinued abruptly. The doseshould be reduced gradually from higher doses to 129 mg daily for 1 to 2weeks before discontinuing.

In some embodiments, the amount of amantadine administered per day isfrom about 50 mg to about 500 mg, from about 50 mg to about 400 mg, fromabout 50 mg to about 300 mg, or from about 50 mg to about 200 mg duringthe Titration Period. In one embodiment, the amount of amantadineadministered per day is about 160 mg, or about 240 mg during theTitration Period. In another embodiment, the amount of amantadineadministered is about 160 mg per day for one week, and then about 240 mgper day for one week, during the Titration Period. In one embodiment,the amount of amantadine free base equivalent administered per day isabout 129 mg, or about 193 mg during the Titration Period. In anotherembodiment, the amount of amantadine administered is about 129 mg perday for one week, and then about 193 mg per day for one week, during theTitration Period. In one embodiment, the pharmaceutical composition isadministered in the morning. In one embodiment, the pharmaceuticalcomposition is administered in the afternoon. In one embodiment, thepharmaceutical composition is administered in the evening. In oneembodiment, the pharmaceutical composition is administered more than 4hours before bedtime.

In some embodiments, the Maintenance Period is from about 10 weeks toabout 100 weeks, from about 10 weeks to about 70 weeks, from about 10weeks to about 50 weeks, from about 10 weeks to about 30 weeks, fromabout 10 weeks to about 25 weeks, from about 10 weeks to about 20 weeks.In some embodiments, the Maintenance Period is at least 10 weeks. Insome embodiments, the Maintenance Period is at least more than 10 weeks.In some embodiments, the Maintenance Period is at least 30 weeks. In oneembodiment, the Maintenance Period is about 12 weeks. In anotherembodiment, the Maintenance Period is about 22 weeks.

In some embodiments, the amount of amantadine administered per day isfrom about 50 mg to about 500 mg, from about 50 mg to about 400 mg, fromabout 50 mg to about 300 mg, or from about 50 mg to about 200 mg duringthe Maintenance Period. In one embodiment, the amount of amantadineadministered per day is about 160 mg, about 240 mg, or about 320 mgduring the Maintenance Period. In another embodiment, the amount ofamantadine free base equivalent administered per day is about 129 mg,about 193 mg, or about 258 mg during the Maintenance Period.

In some embodiments, the Taper Period is from about one week to aboutfour weeks, from about one week to about three weeks, from about oneweek to about two weeks, from about two weeks to about four weeks, fromabout two weeks to about three weeks, or from about three weeks to aboutfour weeks. In some embodiments, the Taper Period is about one week,about two weeks, about three weeks, or about four weeks. In oneembodiment, the Taper Period is about one week. In another embodiment,the Taper Period is about two weeks.

In some embodiments, the amount of amantadine administered per day isfrom about 20 mg to about 300 mg, from about 20 mg to about 250 mg, fromabout 20 mg to about 200 mg, or from about 20 mg to about 100 mg duringthe Taper Period. In one embodiment, the amount of amantadineadministered per day is about 160 mg, or about 240 mg during the TaperPeriod. In another embodiment, the amount of amantadine administered isabout 240 mg per day for one week, and then about 160 mg per day for oneweek, during the Taper Period. In one embodiment, the amount ofamantadine free base equivalent administered per day is about 129 mg, orabout 193 mg during the Taper Period. In another embodiment, the amountof amantadine free base equivalent administered is about 193 mg per dayfor one week, and then about 129 mg per day for one week, during theTaper Period. In one embodiment, the pharmaceutical composition isadministered in the morning. In one embodiment, the pharmaceuticalcomposition is administered in the afternoon. In one embodiment, thepharmaceutical composition is administered in the evening. In oneembodiment, the pharmaceutical composition is administered more than 4hours before bedtime.

Pharmaceutical Compositions

Another aspect of the present disclosure relates to a pharmaceuticalcomposition comprising amantadine. In some embodiments, thepharmaceutical composition is an oral dosage form. The presentdisclosure is not limited to a particular oral dosage form, and anydosage form capable of delivering amantadine to a patients is suitablefor the present invention, so long as the dosage form achievespharmacokinetic and therapeutic effects described in the presentdisclosure. Oral dosage forms are recognized by those skilled in the artto include, but are not limited to, liquid formulations, tablets,capsules, and gelcaps. In one embodiment, the pharmaceutical compositionis a tablet. In some embodiments, the tablets of the invention can beround, biconvex, and white, green or blue coated tablets.

In some embodiments, the present disclosure provides a pharmaceuticalcomposition comprising about 50 mg to about 400 mg of amantadine or apharmaceutically acceptable salt thereof. In some embodiments, thepharmaceutical composition is suitable for oral administration.

In some embodiments, the pharmaceutical composition comprises anadsorbent, antioxidant, buffering agent, colorant, flavorant, sweeteningagent, antiadherent, binder, diluent, direct compression excipient,disintegrant, glidant, lubricant, opaquant and/or polishing agent.

As used herein, the term “adsorbent” is intended to mean an agentcapable of holding other molecules onto its surface by physical orchemical (chemisorption) means. Such compounds include, by way ofexample and without limitation, powdered and activated charcoal andother materials known to one of ordinary skill in the art.

As used herein, the term “antioxidant” is intended to mean an agent thatinhibits oxidation and thus is used to prevent the deterioration ofpreparations by the oxidative process. Such compounds include, by way ofexample and without limitation, ascorbic acid, ascorbyl palmitate,butylated hydroxyanisole, butylated hydroxytoluene, hypophosphorousacid, monothioglycerol, propyl gallate, sodium ascorbate, sodiumbisulfite, sodium formaldehyde sulfoxylate and sodium metabisulfite andother materials known to one of ordinary skill in the art.

As used herein, the term “buffering agent” is intended to mean acompound used to resist change in pH upon dilution or addition of acidor alkali. Such compounds include, by way of example and withoutlimitation, potassium metaphosphate, potassium phosphate, monobasicsodium acetate and sodium citrate anhydrous and dihydrate and othermaterials known to one of ordinary skill in the art.

As used herein, the term “sweetening agent” is intended to mean acompound used to impart sweetness to a preparation. Such compoundsinclude, by way of example and without limitation, aspartame, dextrose,glycerin, mannitol, saccharin sodium, sorbitol and sucrose and othermaterials known to one of ordinary skill in the art.

As used herein, the term “antiadherent” is intended to mean an agentthat prevents the sticking of tablet formulation ingredients to punchesand dies in a tableting machine during production. Such compoundsinclude, by way of example and without limitation, magnesium stearate,talc, calcium stearate, glyceryl behenate, PEG, hydrogenated vegetableoil, mineral oil, stearic acid and other materials known to one ofordinary skill in the art.

As used herein, the term “binder” is intended to mean a substance usedto cause adhesion of powder particles in tablet granulations. Suchcompounds include, by way of example and without limitation, Copovidone(Kollidon VA-64) NF, alginic acid, carboxymethylcellulose sodium,poly(vinylpyrrolidone), compressible sugar (e.g., NuTab™),ethylcellulose, gelatin, liquid glucose, methylcellulose, povidone andpregelatinized starch and other materials known to one of ordinary skillin the art.

When needed, a binder may also be included in the present compositions.Exemplary binders include acacia, tragacanth, gelatin, starch, cellulosematerials such as methyl cellulose and sodium carboxy methyl cellulose,alginic acids and salts thereof, polyethylene glycol, guar gum,polysaccharide, bentonites, sugars, invert sugars, poloxamers (PLURONICF68, PLURONIC F127), collagen, albumin, gelatin, cellulosics innonaqueous solvents, combinations thereof and others known to those ofordinary skill. Other binders include, for example, polypropyleneglycol, polyoxyethylene-polypropylene copolymer, polyethylene ester,polyethylene sorbitan ester, polyethylene oxide, combinations thereofand other materials known to one of ordinary skill in the art.

As used herein, the term “diluent” or “filler” is intended to mean aninert substance used as filler to create the desired bulk, flowproperties, and compression characteristics in the preparation oftablets and capsules. Such compounds include, by way of example andwithout limitation, dibasic calcium phosphate, kaolin, lactose, sucrose,mannitol, microcrystalline cellulose (e.g., Microcrystalline CellulosePH101 NF, and Microcrystalline Cellulose PH200 NF), powdered cellulose,precipitated calcium carbonate, sorbitol, and starch and other materialsknown to one of ordinary skill in the art.

As used herein, the term “direct compression excipient” is intended tomean a compound used in direct compression tablet formulations. Suchcompounds include, by way of example and without limitation, dibasiccalcium phosphate (e.g., Ditab) and other materials known to one ofordinary skill in the art.

As used herein, the term “glidant” is intended to mean agents used intablet and capsule formulations to promote the flowability of agranulation. Such compounds include, by way of example and withoutlimitation, colloidal silica, colloidal silicon dioxide NF, cornstarch,talc, calcium silicate, magnesium silicate, colloidal silicon, siliconhydrogel and other materials known to one of ordinary skill in the art.In some embodiments, the pharmaceutical composition further comprises agranulation solvent, e.g., purified water USP.

As used herein, the term “lubricant” is intended to mean substances usedin tablet formulations to reduce friction during tablet compression.Such compounds include, by way of example and without limitation,magnesium stearate NF, calcium stearate, magnesium stearate, mineraloil, stearic acid, and zinc stearate and other materials known to one ofordinary skill in the art.

As used herein, the term “opaquant” is intended to mean a compound usedto render a capsule or a tablet coating opaque. May be used alone or incombination with a colorant. Such compounds include, by way of exampleand without limitation, titanium dioxide and other materials known toone of ordinary skill in the art.

As used herein, the term “polishing agent” is intended to mean acompound used to impart an attractive sheen to coated tablets. Suchcompounds include, by way of example and without limitation, carnaubawax, and white wax and other materials known to one of ordinary skill inthe art.

As used herein, the term “disintegrant” is intended to mean a compoundused in solid dosage forms to promote the disruption of the solid massinto smaller particles which are more readily dispersed or dissolved.Such disintegrants include, by way of example and without limitation,starches such as corn starch, potato starch, pre-gelatinized andmodified starches thereof, sweeteners, clays, such as bentonite,microcrystalline cellulose (e.g., Avicel), carboxymethylcellulosecalcium, cellulose polyacrilin potassium (e.g., Amberlite), alginates,sodium starch glycolate, gums such as agar, guar, locust bean, karaya,pectin, tragacanth and other materials known to one of ordinary skill inthe art.

As used herein, the term “colorant” is intended to mean a compound usedto impart color to solid (e.g., tablets) pharmaceutical preparations.Such compounds include, by way of example and without limitation, FD&CRed No. 3, FD&C Red No. 20, FD&C Yellow No. 6, FD&C Blue No. 2, D&CGreen No. 5, D&C Orange No. 5, D&C Red No. 8, caramel, and ferric oxide,red, other F.D. & C. dyes and natural coloring agents such as grape skinextract, beet red powder, beta-carotene, annato, carmine, turmeric,paprika, and other materials known to one of ordinary skill in the art.The amount of coloring agent used varies as desired.

As used herein, the term “flavorant” is intended to mean a compound usedto impart a pleasant flavor and often odor to a pharmaceuticalpreparation. Exemplary flavoring agents or flavorants include syntheticflavor oils and flavoring aromatics and/or natural oils, extracts fromplants, leaves, flowers, fruits and so forth and combinations thereof.These may also include cinnamon oil, oil of wintergreen, peppermintoils, clove oil, bay oil, anise oil, eucalyptus, thyme oil, cedar leaveoil, oil of nutmeg, oil of sage, oil of bitter almonds and cassia oil.Other useful flavors include vanilla, citrus oil, including lemon,orange, grape, lime and grapefruit, and fruit essences, including apple,pear, peach, strawberry, raspberry, cherry, plum, pineapple, apricot andso forth. Flavors which have been found to be particularly usefulinclude commercially available orange, grape, cherry and bubble gumflavors and mixtures thereof. The amount of flavoring may depend on anumber of factors, including the organoleptic effect desired. Flavorswill be present in any amount as desired by those of ordinary skill inthe art. Particularly preferred flavors are the cherry flavors andcitrus flavors such as orange.

In some embodiments, the pharmaceutical composition comprises aninternal layer, e.g., a core, and an external layer, e.g., a coat. Insome embodiments, the amantadine in the core is in an extended releaseform and the amantadine in the external coat is in an immediate releaseform. In some embodiments, the total amount of amantadine in thepharmaceutical composition ranges from about 65 mg to about 320 mg. Inone embodiment, the total amount of amantadine is about 160 mg. Inanother embodiment, the total amount of amantadine is about 240 mg. Inanother embodiment, the total amount of amantadine is about 320 mg. Theamount of amantadine in the core generally exceeds the amount present inthe external coat. In some embodiments, the amount of amantadine in thecore ranges from about 50% to about 85% of the total amount present inthe pharmaceutical composition. In some embodiments, the amount ofamantadine in the core ranges from about 60% to about 82% of the totalamount present in the pharmaceutical composition. In one embodiment, theamount of amantadine in the core is about 62% of the total amountpresent in the pharmaceutical composition. In another embodiment, theamount of amantadine in the core is about 75% of the total amountpresent in the pharmaceutical composition. In another embodiment, theamount of amantadine in the core is about 81% of the total amountpresent in the pharmaceutical composition.

In some embodiments of the present invention, the pharmaceuticalcomposition is an osmotic device. In some embodiments, the osmoticdevice comprises an active ingredient (drug) and an osmotic salt(osmotic agent) in the core. In these embodiments, amantadine releasefrom the extended release core of a dosage form of the presentdisclosure invention is controlled by an osmotic pump system. Forexample, an osmotic pump system may comprise of a drug core containedwithin a semipermeable polymer membrane that is permeable to watermolecules but not to the drug. In some embodiments, the osmotic devicefurther comprises an immediate release layer comprising amantadine or apharmaceutically acceptable salt thereof. Amantadine release from theosmotic device is driven by the existence of an osmotic gradient betweenthe contents of the drug core and the fluid in the gastrointestinaltract. Since the osmotic gradient remains constant, drug deliveryremains essentially constant after the immediate-release layerdissolves. The biologically inert components of the osmotic deviceremain intact during gastrointestinal transit and are eliminated in thestool as a tablet shell. In some embodiments, the osmotic devicecomprises a unitary core enclosed with a semipermeable membraneoptionally having at least one preformed passageway there through. Insome embodiments, the unitary core comprises a mixture of amantadinesalt, osmotic salt and one or more pharmaceutical excipients. In someembodiments, the release rate of the active ingredient is reduced andthe release profile of the active ingredient is modified by increasingthe amount of the osmotic salt in the core. In some embodiments, theosmotic salt is an organic salt. In some embodiments, the osmotic saltis an inorganic salt. In some embodiments, the osmotic salt and theamantadine salt have an ion in common. Having an “ion in common” meansthat amantadine salt and the osmotic salt each have ions of the sameidentity. It is not meant that amantadine salt and the osmotic saltactually share the same ion. In some embodiments, the inorganic osmoticsalt is a metal halide. In some embodiments, the inorganic osmotic saltis an alkali metal halide or an earth metal halide. In one embodiment,the inorganic osmotic salt is a sodium chloride. By way of example andwithout limitation, amantadine HCl and NaCl have the chloride ion incommon.

In some embodiments, the osmotic device is capable of providing asigmoidal, pseudo-zero order or zero order release of amantadine or apharmaceutically acceptable salt thereof. In some embodiments, thesigmoidal, pseudo-zero order, or zero order release is from the core ofthe device, once the immediate-release layer is dissolved. In oneparticular embodiment, the release is a zero order release. In anotherembodiment, the release is pseudo-zero order. In some embodiments, therelease of amantadine or a pharmaceutically acceptable salt thereof isessentially constant.

In some embodiments, the unitary core comprises a heterogeneous mixture.In some embodiments, the unitary core comprises a homogeneous mixture. Ahomogeneous mixture is one wherein all of the ingredients have beenthoroughly mixed such that the composition of the formulation issubstantially the same throughout different portions of the core. Thecombined step of mixing and directly compressing the ingredients of thecore generally provides a homogeneous mixture. A heterogeneous mixtureis one wherein the ingredients of the core are divided into two or moregroups that are processed separately to form two or more respectiveblends, at least one of which contains drug and at least one of whichcontains the osmotic salt. The blends are then mixed together andcompressed to form the unitary core. A heterogeneous mixture can beobtained by wet granulation, dry granulation, pelleting or combinationsthereof.

In some embodiments, the osmotic device has a semipermeable membrane.The semipermeable membrane of the osmotic device is formed of a materialthat is substantially permeable to the passage of fluid from theenvironment of use to the core and substantially impermeable to thepassage of active agent from the core. In some embodiments, thesemipermeable membrane comprises a laser drilled orifice for drugdelivery. Many common materials that form a semipermeable wall which areknown by those of ordinary skill in the art of pharmaceutical sciencesare suitable for this purpose.

In some embodiments, the semipermeable membrane comprises at least onefilm forming polymer. In one embodiment, the semipermeable membranecomprises at least two film-forming polymers. In other embodiments, thesemipermeable membrane comprises a plasticizer. Examples of film-formingpolymers include, but are not limited to, cellulose esters, celluloseethers, cellulose esters-ethers, cellulose acylate, or any combinationsthereof. In one embodiment, the film-forming polymer is CelluloseAcetate NF (CA-320S), Cellulose Acetate NF (CA-398-10), or a combinationthereof. In another embodiment, the film-forming polymer is OpadryYellow. Examples of plasticizers include, but are not limited to,polyethylene glycol, propylene glycol, polyesters (e.g. poly (lacticacid), and poly(lactide-co-glycolide)), polyesteramides,diesters/triesters of acids, and diesters/triesters of alcohols.

In one embodiment, the semipermeable membrane comprises celluloseacetate (CA) and poly(ethylene glycol) (PEG). In one embodiment, the PEGis PEG 400. The ratio of CA:PEG generally ranges from about 50-99% byweight of CA: about 50-1% by weight of PEG, and about 95% by weight ofCA: about 5% by weight of PEG. The ratio can be varied to alterpermeability and ultimately the release profile of the osmotic device.In some embodiments, the cellulose acylate is cellulose acetate,cellulose diacetate, cellulose triacetate or any combinations thereof.Many suitable polymers, including those disclosed in Argentine PatentNo. 199,301, U.S. Pat. No. 6,004,582 and other references cited herein,are hereby incorporated by reference.

In some embodiments, the semipermeable membrane comprises at least twodifferent grades of cellulose acetate. Grade 1 cellulose acetate has ahigher viscosity, a higher percentage of hydroxyl groups, and a lowerpercentage of acetyl groups than does grade 2, meaning that grade 2 hasa lower viscosity, lower percentage of hydroxyl groups and higherpercentage of acetyl groups than does grade 1. In some embodiments, thetwo different grades of cellulose acetate are Cellulose Acetate NF(CA-320S) and Cellulose Acetate NF (CA-398-10).

In some embodiments, the semi-permeable membrane further comprises acoating solvent. Examples of coating solvents include, but are notlimited to, ethylcellulose, ethanol, acetone, dichloromethane,isopropanol, and other materials known to one of ordinary skill in theart. In one embodiment, the coating solvent is acetone. In anotherembodiment, the coating solvent is water. In yet another embodiment, thesemi-permeable membrane comprises acetone and purified water USP.

In some embodiments, the osmotic device comprises a water soluble and/orerodible coating, which covers and surrounds the semipermeable membraneand plug any preformed passageway in the membrane if the passageway hadbeen formed prior to addition of the coating. The water soluble and/orerodible coating is described in detail above.

In some embodiments, the osmotic device comprises a color separationcoating over the semi-permeable membrane. The color separating coatingcan comprise a film forming polymer, a coating solvent, or a combinationthereof.

In some embodiments, the osmotic device further comprises an IR layercomprising amantadine or a pharmaceutically acceptable salt thereof. Insome embodiment, the IR layer further comprises a film forming polymer.In another embodiment, the IR layer comprises a coating solvent.Examples of film-forming polymers and coatings solvents are listed aboveand can also include other materials known to one of ordinary skill inthe art.

In some embodiments, the osmotic device further comprises an aestheticcoating comprising a film forming polymer and a coating solvent.Examples of film-forming polymers and coatings solvents are listed aboveand can also include other materials known to one of ordinary skill inthe art. In one embodiment, the film forming polymer is Opadry White(Y-30-18037), Opadry Green (15B110000), Opadry Blue (15B105001), or anycombinations thereof. In one embodiment, the coating solvent is purifiedwater.

In some embodiment, the osmotic device further comprises a printing. Inone embodiment, the printing is ink (e.g., Opacode WB NS-78-17821Black).

Method of Preparation of the Pharmaceutical Compositions

The pharmaceutical compositions can be prepared according to the methodsdisclosed herein or those well known in the art.

In the embodiment related to an osmotic device, the active agent andexcipients that comprise the core are mixed in solid, semisolid orgelatinous form, then moistened and sieved through a specified screen toobtain a granulate. The granulate is then dried in a dryer andcompressed, for example, by punching to form uncoated cores. Thecompressed and uncoated cores are then covered with a solution ofsuitable materials that comprise the wall. Subsequently, the wallsurrounding each core is perforated with, for example, laser equipmentto form the preformed passageway in the manner previously described. Insome embodiments, a drug-containing external coat is applied to coverthe wall as a sprayed coating or a compression coating. In someembodiments, the osmotic device is coated with a finish coat as iscommonly done in the art to provide the desired shine, color, taste orother aesthetic characteristics. Materials suitable for preparing thefinish coat are well known in the art and found in the disclosures ofmany of the references cited and incorporated by reference herein.

Combination Therapy

Amantadine may be administered as a combination with a second agent fortreatment of Parkinson's Disease. Amantadine may also be administered asa combination with a second agent for treatment of drug-inducedextrapyramidal reactions. Additionally, amantadine may be administeredas a combination with a second agent for treatment of levodopa-induceddyskinesia. In some embodiments, the second agent comprises one or morecompounds selected from the group consisting of levodopa and/or anotherdrug selected from the group consisting of an aromatic-L-amino-aciddecarboxylase inhibitor such as carbidopa or benserezide; dopamineagonists such as apomorphine, bromocriptine, cabergoline, lisuride,pergolide, pramipexole, ropinirole, and rotigotine; COMT (catecholO-methyltransferase) inhibitors such as entacapone, tolcapone and BIA9-1067 (opicapone); MAO-B (monoamine oxidase B) inhibitors such asselegiline, rasagiline and safinamide; anticholinergics such astrihexyphenidyl, benztropine, orphenadrine, procyclidine, ethopropazine,and glycopyrrolate; benzodiazepines such as alprazolam, lorazepam,diazepam, clonazepam; SSRIs (selective serotonin reuptake inhibitors)such as fluoxetine, sertraline, paroxetine and fluvoxamine; tricyclicand tetracyclic antidepressants such as mirtazapine, doxepin,imipramine, desipramine, trazodone, and nortriptyline; nonsteroidalanti-inflammatory agents such as minocycline and COX-2(cyclooxygenase-2) inhibitors; non-narcotic analgesic such asacetaminophen, aspirin, diclofenac, diflusinal, etodolac, fenbufen,flufenisal, flurbiprofen, ibuprofen, indomethacin, ketoprofen,ketorolac, meclofenamic acid, mefenamic acid, nabumetone, naproxen,oxaprozin, phenylbutazone, piroxicam, sulindac, tolmetin, tramadol andzomepiracadenosine; narcotic analgesics such as codeine, dihydrocodeine,hydrocodone, hydromorphone, levorphanol, morphine, oxycodone andtapentadol; ADORA2A (adenosine A2A receptor) antagonists such aspreladenant, tozadenant, DT-1133 and DT1687; anti-epileptic agentsselected from the group consisting of AMPA antagonists, Benzodiazepines,Barbiturates, Valproates, GABA analogs, Iminostilbenes, Hydantoins, NMDAantagonists, Sodium channel blockers, Carboxylic acids,oxazolidinediones, succinimides, pyrrolidines, sulphonamides,aminobutyric acids, sulfamate-substituted monosaccharides, carboxamides,aromatic allylic alcohols, ureas, phenyltriazines, carbamates,pyrrolidines, losigamone, retigabine, rufinamide, acetazolamide,clomthiazole edisilate, zonisamide, felbamate, topiramate, tiagabine,levetiracetam, briveracetam, SPD 421 (DP-VPA), T-2000, XP-13512,GSK-362115, GSK-406725, ICA-69673, CBD cannabis derivative,isovaleramide (NPS-1776), carisbamate, safinamide, seletracetam,soretolide, stiripentol, and valrocemide; lacosamide, gabapentin,indomethacin, steroids, fluorocortisone, desmopressin, oxybutynin,tolterodine, hyoscyamine, midodrine, phenylephrine, phenylpropanolamine,baclofen, dantrolene, domperidone, mosapride, tegaserod, donepezil,memantine, riluzole, rivastigmine, coenzyme Q10, vitamin E, vitamin C,creatine, ginkgo biloba, nicotinamide, carnitine, piribedil, buspirone,clozapine, quetiapine, olanzapine, risperidone, aripiprazole,methylphenidate, modafinil, dipraglurant, fipamezole, AFQ056, AQW-051,Neu-120, olesoxime, 17-B-hydroxyepiandrosterone, (+)-phenserine,clavulanic acid, HE-3286, YM-50018, MCD-386, AV-101, SUVN-502, EVP-0334,V-81444, SCH-900800, ADX-88178, NNZ-2591, AEOL-11207, Proximagen,IC-200214, SIG-1012, ADL-5510, TrkB PAM, and G-79.

In some embodiments, the second agent is present in an amount known tobe therapeutically (clinically) effective for the treatment of a targetcondition, disease or disorder, such as those described herein, when aunit dose of the pharmaceutical composition is administered to a subjectin need thereof. Guidance as to the therapeutically effective amount ofeach previously marketed second agent can be obtained from the Food andDrug Administration (USA, www.fda.gov), European Medicines Agency(Europe, ema.europa.eu), National Institute of Health Sciences (Japan,www.nihs.go.jp), and National Administration of Drugs, Food, and MedicalTechnology (Administración Nacional de Medicamentos, Alimentos yTecnología Médica, Argentina, www.anmat.gov.ar), the disclosures ofwhich are incorporated herein by reference in their entirety. Forexample, the package insert for any approved drug includes dosage andadministration information, which can be used to determine the properamount of each drug to be included in a pharmaceutical composition ofthe invention. The amounts for a particular drug combination inaccordance with this invention can be determined employing routineexperimental testing. If the drugs are present in such a weight ratiothat a super-additive or synergistic therapeutic effect is observed uponadministration to the patients, the overall administered dose may belowered, so that fewer undesired side-effects will occur.

In some embodiments, the pharmaceutical composition comprises acombination of amantadine and one or more other drugs, and may containan excess of amantadine, an excess of the one or more other drugs, orequivalent amounts of amantadine and the one or more other drugs. Theweight ratio of amantadine to the one or more other drugs can range fromabout 100:1 to 1:100. In one embodiment, the one or more other drugs areadministered to the subject, sequentially or concomitantly, in anotherdosage form such that the subject receives a dose of the one or moreother drugs in the pharmaceutical composition and a dose of the one ormore other drugs in another dosage form. The dosing regimen for the oneor more other drugs can thus be the same as or different than the dosingregimen for amantadine.

In some embodiments, the pharmaceutical composition comprises anexternal coat comprising a second active agent for immediate release ofthe drug. In some embodiments, the osmotic device comprises a coatexternal to the semipermeable membrane. The external coat can be a rapidrelease coat. In some embodiments, the second active ingredient in theexternal rapid release coat is selected from the group consisting ofamantadine, cabergoline, pergolide, selegiline, rasagiline,trihexyphenidyl, benztropine, donepezil, fluoxetine, sertraline,paroxetine, fluvoxamine, mirtazapine, doxepin, desipramine, clozapine,olanzapine, risperidone, aripiprazole, fludrocortisone, safinamide, andsmilagenin. In some embodiments, the osmotic device comprises anon-absorbable shell.

In Vitro Assays

The pharmaceutical compositions prepared according to certainembodiments of the present invention preferably exhibit the followingdissolution profile when tested in a USP Type II dissolution apparatus(paddles), using water or in 0.1N HCl as a dissolution media, with afixed agitation rate of 50 revolutions per minute, maintained at atemperature of about 37±0.5° C. In some embodiments, the pharmaceuticalcomposition has an in vitro dissolution profile ranging between about0.1% to about 50% in about 0.5 hour, about 20% to about 80% in about 2.5hours, about 40% to about 90% in about 4 hours, and no less than about85% in about 8 hours using water as a dissolution media. In oneembodiment, the pharmaceutical composition has an in vitro dissolutionprofile ranging between about 28% to about 48% in about 0.5 hour, about39% to about 63% in about 2.5 hours, about 61% to about 85% in about 4hours, and no less than about 85% in about 8 hours using water as adissolution media. In another embodiment, the pharmaceutical compositionhas an in vitro dissolution profile ranging between about 15% to about35% in about 0.5 hour, about 29% to about 53% in about 2.5 hours, about53% to about 77% in about 4 hours, and no less than about 85% in about 8hours using water as a dissolution media. In another embodiment, thepharmaceutical composition has an in vitro dissolution profile rangingbetween about 9% to about 29% in about 0.5 hour, about 37% to about 62%in about 2.5 hours, about 59% to about 83% in about 4 hours, and no lessthan about 85% in about 8 hours using water as a dissolution media. Inone embodiment, the pharmaceutical composition has an in vitrodissolution profile ranging between about 0.1% to about 10% in about 1hour, about 20% to about 60% in about 2.5 hours, about 40% to about 80%in about 4 hours, about 70% to about 95% in about 6 hours, and no lessthan about 85% in about 8 hours. In another embodiment, thepharmaceutical composition has an in vitro dissolution profile in waterranging between about 0.1% to about 10% in about 1 hour, about 5% toabout 50% in about 2.5 hours, about 40% to about 80% in about 4 hours,about 70% to about 95% in about 6 hours, and no less than about 85% inabout 8 hours. In another embodiment, the pharmaceutical composition hasan in vitro dissolution profile in water ranging between about 0.1% toabout 10% in about 1 hour, about 5% to about 60% in about 2.5 hours,about 40% to about 90% in about 4 hours, about 80% to about 97% in about6 hours, and no less than about 95% in about 8 hours. In someembodiments, an extended release pharmaceutical composition comprisingamantadine has an in vitro dissolution profile in a solution with aneutral pH (e.g., water) that is substantially the same as itsdissolution profile in an acidic dissolution medium.

Pharmacokinetics

Amantadine in an extended release form is released into a subject sampleat a slower rate than observed for an immediate release formulation ofthe same quantity of amantadine, such that the rate of change in thebiological sample is measured as the dC/dT over a defined period.

In some embodiments, the dC/dT of amantadine is less than about 80%,about 70%, about 60%, about 50%, about 40%, about 30%, or about 20% ofthe dC/dT provided by the same quantity of amantadine in an immediaterelease form, when the dC/dT is measured between 0 and 4 hours afteradministration. In some embodiments, the dC/dT of amantadine is greaterthan about 30%, about 40% and about 50% of the dC/dT provided by thesame quantity of amantadine in an immediate release form, when the dC/dTis measured between 0 and 4 hours after administration. In oneembodiment, the dC/dT of amantadine is greater than about 50% of thedC/dT provided by the same quantity of amantadine in an immediaterelease form, when the dC/dT is measured between 0 and 4 hours afteradministration.

In some embodiments, the dC/dT of amantadine is from about 40% to about70%, from about 40% to about 60%, from about 40% to about 50%, fromabout 50% to about 60%, from about 50% to about 70%, from about 60% toabout 70% of the dC/dT provided by the same quantity of amantadine in animmediate release form, when the dC/dT is measured between 0 and T_(max)for the IR formulation after administration. In one embodiment, thedC/dT of amantadine is about 45% of the dC/dT provided by the samequantity of amantadine in an immediate release form, when the dC/dT ismeasured between 0 and T_(max) for the IR formulation afteradministration. In another embodiment, the dC/dT of amantadine is about55% of the dC/dT provided by the same quantity of amantadine in animmediate release form, when the dC/dT is measured between 0 and T_(max)for the IR formulation after administration. In another embodiment, thedC/dT of amantadine is about 70% of the dC/dT provided by the samequantity of amantadine in an immediate release form, when the dC/dT ismeasured between 0 and T_(max) for the IR formulation afteradministration.

In some embodiments, amantadine is formulated to release at a rate thatis significantly reduced over an immediate release dosage form, with anassociated delay in the mean T_(max). In some embodiments, thepharmaceutical composition is formulated to provide a shift in T_(max)by about 16 hours, about 14 hours, about 12 hours, about 10 hours, about9 hours, about 8 hours, about 7 hours, about 6 hours, about 5 hours,about 4 hours, about 3 hours, about 2 hours, or about 1 hour.

In some embodiments, the T_(max) of the pharmaceutical composition isbetween about 5 and about 12 hours, between about 5 and about 10 hours,between about 5 and about 8 hours, between about 5 and about 6 hours,between about 6 and about 12 hours, between about 6 and about 10 hours,between about 6 and about 8 hours, between about 7 and about 12 hours,between about 7 and about 10 hours, between about 7 and about 8 hours,between about 8 and about 12 hours, between about 8 and about 10 hours,between about 9 and about 12 hours, between about 9 and about 10 hours,or between about 10 and about 12 hours. In one embodiment, the medianT_(max) of the pharmaceutical composition is about 7.5 hours.

In some embodiments, the pharmaceutical composition comprising anextended release amantadine reduces the dC/dT of the drug, and not onlyincreases mean T_(max), but also reduces mean C_(max) (the drugconcentration at T_(max)) and reduces the C_(max)/C_(mean) ratioproviding a more constant amount of drug to the subject being treatedover a given period of time, enabling increased dosages for appropriateindications. In some embodiments, the mean C_(max) of the pharmaceuticalcomposition after a single-dose administration is between about 200 andabout 1000 ng/ml, between about 200 and about 900 ng/ml, between about200 and about 800 ng/ml, between about 200 and about 700 ng/ml, betweenabout 200 and about 600 ng/ml, between about 200 and about 500 ng/ml,between about 200 and about 400 ng/ml, between about 200 and about 300ng/ml, between about 300 and about 1000 ng/ml, between about 300 andabout 900 ng/ml, between about 300 and about 800 ng/ml, between about300 and about 700 ng/ml, between about 300 and about 600 ng/ml, betweenabout 300 and about 500 ng/ml, between about 300 and about 400 ng/ml,between about 400 and about 1000 ng/ml, between about 400 and about 900ng/ml, between about 400 and about 800 ng/ml, between about 400 andabout 700 ng/ml, between about 400 and about 600 ng/ml, between about400 and about 500 ng/ml, between about 500 and about 1000 ng/ml, betweenabout 500 and about 900 ng/ml, between about 500 and about 800 ng/ml,between about 500 and about 700 ng/ml, between about 500 and about 600ng/ml.

In some embodiments, the mean C_(max) of the pharmaceutical compositionafter a single-dose administration is between about 540 and about 895ng/ml. In one embodiment, the pharmaceutical composition comprises about320 mg amantadine. In some embodiments, the mean C_(max) of thepharmaceutical composition after a single-dose administration is betweenabout 370 and about 550 ng/ml. In one embodiment, the pharmaceuticalcomposition comprises about 240 mg amantadine. In some embodiments, themean C_(max) of the pharmaceutical composition after a single-doseadministration is between about 265 and about 390 ng/ml. In oneembodiment, the pharmaceutical composition comprises about 160 mgamantadine. In some embodiments, after a single oral administration ofthe 129 mg amantadine free base equivalent, the mean (CV %) C_(max) is328 ng/ml (18%). C_(max) with other dose levels of the pharmaceuticalcomposition increases proportionally.

Another PK parameter of interest is the resulting area under the plasmaconcentration-time curve (AUC_(0-∞)), calculated to the last measuredconcentration (AUC_(0-T)) and extrapolated to infinity (AUC_(t-∞)), forextent of absorption of amantadine. In some embodiments, the meanAUC_(0-∞) of the pharmaceutical composition after a single-doseadministration is between about 6,000 and about 24,000 ng·h/mL, betweenabout 6,000 and about 20,000 ng·h/mL, between about 6,000 and about16,000 ng·h/mL, between about 6,000 and about 12,000 ng·h/mL, betweenabout 6,000 and about 10,000 ng·h/mL, between about 6,000 and about8,000 ng·h/mL, between about 8,000 and about 24,000 ng·h/mL, betweenabout 8,000 and about 20,000 ng·h/mL, between about 8,000 and about16,000 ng·h/mL, between about 8,000 and about 12,000 ng·h/mL, betweenabout 8,000 and about 10,000 ng·h/mL, between about 10,000 and about24,000 ng·h/mL, between about 10,000 and about 20,000 ng·h/mL, betweenabout 10,000 and about 16,000 ng·h/mL, between about 10,000 and about12,000 ng·h/mL, between about 12,000 and about 24,000 ng·h/mL, betweenabout 12,000 and about 20,000 ng·h/mL, between about 12,000 and about16,000 ng·h/mL, between about 16,000 and about 24,000 ng·h/mL, betweenabout 16,000 and about 20,000 ng·h/mL, or between about 20,000 and about24,000 ng·h/mL.

In some embodiments, the mean AUC_(0-∞) of the composition after asingle-dose administration is between about 12,000 and about 26,000ng·h/mL. In some embodiments, the mean AUC_(0-∞) of the compositionafter a single-dose administration is between about 12,500 and about23,500 ng·h/mL. In one embodiment, the pharmaceutical compositioncomprises about 320 mg amantadine HCl. In some embodiments, the meanAUC_(0-∞) of the composition after a single-dose administration isbetween about 8,000 and about 20,000 ng·h/mL. In some embodiments, themean AUC_(0-∞) of the composition after a single-dose administration isbetween about 10,400 and about 15,900 ng·h/mL. In one embodiment, thepharmaceutical composition comprises about 240 mg amantadine HCl. Insome embodiments, the mean AUC_(0-∞) of the composition after asingle-dose administration is between about 6,000 and about 26,000ng·h/mL. In some embodiments, the mean AUC_(0-∞) of the compositionafter a single-dose administration is between about 6,900 and about10,300 ng·h/mL. the mean AUC_(0-∞) of the composition after asingle-dose administration is between about 6,000 and about 12,000ng·h/mL. In one embodiment, the pharmaceutical composition comprisesabout 160 mg amantadine HCl. In some embodiments, after a single oraladministration of the 129 mg amantadine free base equivalent, the meanAUC_(0-∞) is about 8580 ng·h/mL with other dose levels of thepharmaceutical composition increasing proportionally.

In some embodiments, the relative bioavailability of amantadine or apharmaceutically acceptable salt thereof is approximately the same underfed and fasting conditions.

Efficacy

In the present invention, treatment of patients with an extended releaseamantadine dosage form of the present invention improves symptoms of PD,extrapyramidal reactions, and/or levodopa-induced dyskinesia.

In some embodiments, treatment of patients with an extended releaseamantadine dosage form of the present invention improves dyskinesia in apatient with levodopa-induced dyskinesia (LID) as determined by areduction in a total Unified Dyskinesia Rating Scale (UdysRS) scoreafter twelve weeks. In some embodiments, the treatment increases thenumber of awake ON hours without dyskinesia in the patient.

In some embodiments, the reduction in UdysRS score is between about −2and about −7, between about −2 and about −6, between about −2 and about−5, between about −2 and about −4, between about −2 and about −3,between about −3 and about −7, between about −3 and about −6, betweenabout −3 and about −5, between about −3 and about −4, between about −4and about −7, between about −4 and about −6, between about −4 and about−5, between about −5 and about −7, between about −5 and about −6, orbetween about −6 and about −7, after twelve weeks, compared to placebo.In one embodiment, the reduction in UdysRS score is about −5 aftertwelve weeks, compared to placebo.

In some embodiments, the reduction in UdysRS score is between about −9and about −17, between about −9 and about −16, between about −9 andabout −15, between about −9 and about −14, between about −9 and about−13, about −9 and about −12, about −9 and about −11, about −9 and about−10, between about −10 and about −17, between about −10 and about −16,between about −10 and about −15, between about −10 and about −14,between about −10 and about −13, about −10 and about −12, about −10 andabout −11, between about −11 and about −17, between about −11 and about−16, between about −11 and about −15, between about −11 and about −14,between about −11 and about −13, about −11 and about −12, between about−12 and about −17, between about −12 and about −16, between about −12and about −15, between about −12 and about −14, between about −12 andabout −13, between about −13 and about −17, between about −13 and about−16, between about −13 and about −15, between about −13 and about −14,between about −14 and about −17, between about −14 and about −16,between about −14 and about −15, between about −15 and about −17,between about −15 and about −16, or between about −16 and about −17,after twelve weeks. In one embodiment, the reduction in UdysRS score isabout −13 after twelve weeks.

In some embodiments, the method increases the number of awake ON hourswithout dyskinesia in the patient by about 1 to about 4 hours, by about1 to about 3 hours, by about 1 to about 2 hours, by about 2 to about 4hours, by about 2 to about 3 hours, or by about 3 to about 4 hours aftertwelve weeks. In one embodiment, the method increases the number ofawake ON hours without dyskinesia in the patient by about 4 hours aftertwelve weeks.

In some embodiments, the number of awake ON hours without dyskinesia inthe patient is between about 9 and about 14 hours, between about 9 andabout 13 hours, between about 9 and about 12 hours, between about 9 andabout 11 hours, between about 9 and about 10 hours, between about 10 andabout 14 hours, between about 10 and about 13 hours, between about 10and about 12 hours, between about 10 and about 11 hours, between about11 and about 14 hours, between about 11 and about 13 hours, betweenabout 11 and about 12 hours, between about 12 and about 14 hours,between about 12 and about 13 hours, or between about 13 and about 14hours.

In some embodiments, MDS-UPDRS (Movement Disorder Society-UnifiedParkinson's Disease Rating Scale) Part II and III is used to assess anypotential worsening of PD symptoms. In some embodiments, the method doesnot worsen Parkinson's disease symptoms in the subjects (patients).

Indications

The pharmaceutical compositions of the present invention are suitablefor the treatment of diseases, disorders and/or symptoms that aretherapeutically or clinically responsive to amantadine therapy. In someembodiments, diseases, disorders and/or symptoms that are responsive toamantadine therapy include, but are not limited to, Parkinson's disease,parkinsonism, drug-induced extrapyramidal reactions (including, forexample, akathisia, dystonia or dyskinesia), levodopa-induceddyskinesia, viral infection, and signs and symptoms of infection causedby various strains of influenza A virus, especially for high-riskpatients such as those in critical public-service positions,immunosuppressed patients, nursing home residents, contacts of high-riskpatients, and those with severe influenza A viral infection.

The pharmaceutical compositions of the present invention can beadministered for the treatment of elderly patients believed to developParkinsonism in association with or as a result of cerebralarteriosclerosis or another neurodegenerative disease, dementia inParkinson's disease, fatigue associated with multiple, reducing relapsesin multiple sclerosis, improving symptoms of attention deficithyperactivity disorder (ADHD), SSRI-induced sexual dysfunction,management of addictions and substance dependence, resistant unipolardepression, bipolar disorders, Alzheimer's Disease, senile dementia,Huntington's disease, neuropathic pain, postoperative pain, refractoryabsence seizures, brain injury, and traumatic brain injury.

In some embodiments, the pharmaceutical compositions of the presentinvention are suitable for the treatment of a disease or a disorderselected from the group consisting of Parkinson's disease, drug-inducedextrapyramidal reactions, levodopa-induced dyskinesia, and anycombinations thereof.

In some embodiments, the pharmaceutical compositions of the presentinvention are suitable for the treatment of Parkinson's disease.

In another embodiment, the pharmaceutical compositions of the presentinvention are suitable for the treatment of drug-induced extrapyramidalreactions.

In another embodiment, the pharmaceutical compositions of the presentinvention are suitable for the treatment of levodopa-induced dyskinesia.

In some embodiments, the drug-induced extrapyramidal reactions include,but are not limited to, dystonia (continuous spasms and musclecontractions), akathisia (motor restlessness), parkinsonism(characteristic symptoms such as rigidity), bradykinesia (slowness ofmovement), tremor, tardive dyskinesia (irregular, jerky movements), andother side effects caused by antipsychotics.

In some embodiments, the drug-induced extrapyramidal reactions arecaused by, but not limited to, antipsychotic drugs, such as haloperidol,fluphenazine, thilthixene, trifluoroperazine, acetophenazine,prochlorperazine, perphenazine, loxapine, chlorpromazine,triflupromazine, molindone, mesoridazine, chlorprothixene, thioridazine,clozapine; other anti-dopaminergic drugs, such as antiemeticmetoclopramide, trimethobenzamide (e.g., Tigan®) and metoclopramide(e.g., Reglan®), other substituted benzamides; antidepressants, such asselective serotonin reuptake inhibitors (SSRI), serotonin-norepinephrinereuptake inhibitors (SNRI), and norepinephrine-dopamine reuptakeinhibitors (NDRI), desipramine (e.g., Norpramin®), protriptyline (e.g.,Vivactil®). duloxetine, sertraline, escitalopram, fluoxetine, andbupropion; concomitantly using neuroleptics and lithium; anticonvulsantagents such as phenytoin (e.g., Dilantin®) and carbamazepine (e.g.,Tegretol®); and oral contraceptives.

In a specific embodiment, the patient has Parkinson's disease, which, asused herein, also encompasses a diagnosis of parkinsonism. In oneembodiment, the patient has early stage Parkinson's disease, and thepharmaceutical composition of the present invention is administered as amonotherapy or in combination with a MAO-B inhibitor without concomitantuse of levodopa. In another embodiment, the patient has late stageParkinson's disease and the patient takes levodopa in addition to thepharmaceutical composition of the present invention. In anotherembodiment, the patient has multiple sclerosis and the pharmaceuticalcomposition of the present invention is used for the treatment ofwalking impairment (that is, improve walking mobility, distance andspeed), and to reduce or to relieve fatigue.

The pharmaceutical compositions of the present invention are alsosuitable for the treatment of diseases, disorders and/or symptoms thatare responsive to a combination of amantadine and a second drug. In someembodiments, the invention includes an osmotic device for the combinedadministration of amantadine in a controlled release manner and anantidepressant in an immediate or rapid release manner, e.g., thecombination of amantadine and citalopram, fluoxetine, paroxetine,sertraline, fluvoxamine or escitalopram. In some embodiments, theinvention also includes an osmotic device for the combinedadministration of amantadine in a controlled release manner and ananxiolytic agent in an immediate or rapid release manner, e.g.,amantadine and buspirone or trazodone, for the amelioration of undesiredtremors, akinesia, dyskinesia, or bradykinesia associated with one ormore different disorders or diseases. In some embodiments, the inventionalso includes an osmotic device for the combined administration ofamantadine and a second anti-Parkinsonian drug in a controlled releasemanner from the core, e.g., amantadine and ropinirole, or selegiline, orlevodopa-carbidopa. The term “anti-Parkinsonian drug” means a drug knownin the art for use in treating Parkinson's disease.

In some embodiments, amantadine is combined with an active agentselected from narcotic analgesics, gabapentin and/or lacosamide tocontrol a patient's pain. Examples of medical conditions and/or types ofpain that can be treated with such an osmotic device include acuteinflammatory pain; acute pain; alcoholism-associated oralcoholism-induced neuropathic pain; allodynia (occurring independentlyor as a symptom of another condition); arthritic conditions; back pain;cancer-related neuropathic pain, e.g., painful compression by tumorgrowth of adjacent nerves, the brain or the spinal cord; centralneuropathic pain; chronic headache; chronic inflammatory pain; chronicpain; chronic pain due to peripheral nerve injury; diabetes-associatedor diabetes-induced neuropathic pain; diabetic pain; diabetic distalsensory neuropathy; diabetic distal sensory polyneuropathy;fibromyalgia; headache; hyperalgesia (occurring independently or as asymptom of another condition); hyperesthesia; hyperpathia; migraine,including classical migraine and common migraine; myalgia; myofascialpain syndrome; neuralgia; neuroma; non-inflammatory musculoskeletalpain; non-inflammatory osteoarthritic pain; non-neuropathic inflammatorypain; neuropathic pain; pain associated with or induced by chemotherapyor radiation therapy; pain associated with or induced by traumatic nerveinjury or compression or by traumatic injury to the brain or spinalcord; painful diabetic neuropathy; peripheral neuropathic pain;persistent clinical pain; phantom pain; rheumatoid arthritis pain;secondary inflammatory osteoarthritic pain; trigeminal neuralgia; andvascular headache.

EXAMPLES Example 1 Amantadine Tablet Formulation

Amantadine HCl Extended Release (ER) Tablets, 160, 240 and 320 mg (eachtablet contains 129 mg, 193 mg, or 258 mg amantadine fee baseequivalent, respectively) were manufactured as described herein. Thetablets contain an extended release core and an immediate release layer.

Amantadine release from the extended release core is controlled by anosmotic pump system. The osmotic pump system consists of a drug corecontained within a semipermeable polymer membrane that is permeable towater molecules but not to the drug with a laser drilled orifice fordrug delivery. Amantadine release is driven by the existence of anosmotic gradient between the contents of the drug core and the fluid inthe gastrointestinal tract. Since the osmotic gradient remains constant,drug delivery remains essentially constant after the immediate-releaselayer dissolves. The biologically inert components of the tablet remainintact during gastrointestinal transit and are eliminated in the stoolas a tablet shell.

Amantadine HCl core was coated with a semi-permeable membrane (CoatingA) and laser drilled to provide an orifice. The extended release corewas coated with the following 3 additional coatings: a color separationcoating (Coating B), an amantadine HCl immediate release layer (CoatingC), and a non-performance color coating (Coating D) with blackimprinting.

The formulation was designed to provide for once-a-day dosing; theimmediate release component was included to eliminate a lag time. Thecore composition is the same for all three tablet strengths, the weightof the core increases dose proportionally with increasing dose. Theunit-dose composition for Amantadine HCl ER Tablets, 160, 240 and 320 mgis provided in Table 1.

TABLE 1 Summary of Unit-Dose Amantadine HCl ER Tablet Composition byTablet Strength 160 mg 240 mg 320 mg Ingredient mg/tablet % w/wmg/tablet % w/w mg/tablet % w/w Tablet Core Amantadine 100.00 30-50180.00 35-55 260.00 40-60 Hydrochloride USP (Active) Osmotic Agent 4-92-3  9-14 2-4 13-20 2-5 Binder  4-10 2-4 10-16 2-5 15-24 2-5 Filler 123-29  8-12 40-54 10-14 54-72 10-16 Filler 2  6-10 2-4 11-18 2-5 16-263-5 Glidant 0.5-0.8 0.2-0.3 0.5-2   0.2-0.4 1-2 0.2-0.5 Lubricant  1-1.5 0.4-0.6 1-3 0.2-1   2-4 0.4-0.8 Granulation 25-35 44-64 63-83Solvent Final Core 120-180 210-330 310-470 weight (mg) Osmotic Coating(Coating A) Film forming  6-10 2-4  8-15 2-4  8-15 1-3 polymer 1 Filmforming  6-10 2-4  8-15 2-4  8-15 1-3 polymer 2 Plasticizer 0.5-1  0.2-0.5 0.8-2   0.2-0.6 0.8-2   0.1-0.5 Coating Solvent 1 200-300300-400 300-400 Coating Solvent 2 30-50 50-70 50-70 Osmotic Coating12-21 20-30 20-30 weight (mg) Coated Tablet 130-200 230-360 330-500weight (mg) Color Separation Coating (Coating B) Film forming 4-61.5-2.5  7-11 1.8-3    9-15 1.8-3   polymer Coating Solvent 38-54 64-98 85-130 Coated Tablet 135-205 235-365 342-512 weight (mg) IR Layer(Coating C) Active  60.00 18-30  60.00 12-18  60.00  8-14 Film forming11-18 4-8 11-18 3-5 11-18   2-3.5 polymer Coating Solvent 300-500300-500 300-500 IR Layer 60-90 60-90 60-90 weight (mg) IR Coated Tablet200-300 300-450 400-600 weight (mg) Aesthetic Coating (Coating D) Filmforming 6-9 2.5-3.5 polymer 1 Film forming —  9-14 2.5-3.5 polymer 2Film forming — 10-20 2-4 polymer 3 Coating Solvent 50-80 80-130 100-170Coated Tablet 200-300 300-500 400-600 weight (mg) Printing (Optional)Ink Total Tablet 200-300 100.00% 300-500 100.00% 400-600 100.00% weight(mg) ¹Removed during manufacturing process

Example 2 Biopharmaceutic Studies and Associated Analytical Methods 2.1Background and Overview

Three clinical studies were conducted to compare relativebioavailability of Amantadine HCl ER Tablets, 160 mg, 240 mg and 320 mg,and an immediate release amantadine oral syrup formulation. AmantadineHCl ER Tablets were manufactured as described in Example 1. AmantadineHCl syrup, 50 mg/5 mL (amantadine HCl oral solution, USP), ANDA 075060,was the approved immediate-release product (Reference Listed Drug, RLD)and used as reference product in the comparative bioavailabilitystudies.

The three bioavailability studies were carried out in healthyvolunteers:

-   -   1. Study I compared the steady-state bioavailability of        amantadine from one Amantadine HCl ER 320 mg Tablet administered        orally once daily to 160 mg amantadine HCl syrup, 50 mg/5 mL        administered orally twice daily for 7 days;    -   2. Study II compared the single-dose bioavailability and        pharmacokinetics of Amantadine HCl ER Tablets, at 160 mg, 240        mg, and 320 mg to a single oral 160 mg dose of amantadine HCl        syrup, 50 mg/5 mL; and    -   3. Study III evaluated the effect of a high-fat meal on        amantadine bioavailability for Amantadine HCl ER Tablets, at 320        mg.

2.2 Summary of Results of Individual Studies 2.2.1 Study III (RelativeBioavailability of Amantadine HCl ER Tablet, 320 mg Under Fasting andFed Conditions)

Study III was an open-label, balanced, randomized, two-period,two-sequence, single dose, bioavailability study under fasting and fedconditions of Amantadine HCl 320 mg ER Tablets in normal, healthy, adultmale and female volunteers.

In each study period, 22 blood samples (4 mL each), including onepre-dose blood sample were collected from each subject. There were 7days between dosing periods. The following 2 treatments wereadministered: Amantadine HCl 320 mg ER tablets given under fastingconditions (Test-T1, Fasted), and Amantadine HCl 320 mg ER tablets givenunder fed conditions (Test-T2, Fed).

Dosing Under Fasting Conditions

After an overnight fast of at least 10 hours, a single oral dose (320mg) of the test product was administered to the subjects with 240 mL ofdrinking water at ambient temperature in sitting posture.

Dosing Under Fed Conditions

After an overnight fast of at least 10 hours, the subjects were served ahigh fat meal, which they consumed within 30 minutes. A single oral dose(320 mg) of the test product was administered to the subjects at 30minutes after serving the high fat meal. The standard high fat mealconsisted of: 2 eggs fried in butter, 2 strips of bacon, 2 slices oftoast with butter, 4 ounces of hash brown potatoes, and 8 fluid ounces(˜240 mL) of whole milk. The test product was administered in sittingposture with 240 mL of drinking water at ambient temperature.

The dosing activity was followed by a mouth and hands check to assessthe compliance to dosing. The test product administration was as per therandomization schedule and under open-label conditions.

Results

Subjects enrolled and completed both treatment periods. The mean age was40.8 years, and the mean BMI was 26.75 kg/m².

Pharmacokinetic Results

A summary of the descriptive statistics for the amantadinepharmacokinetic parameter values are summarized in Table 2.

TABLE 2 Descriptive Statistics of Treatment Mean Pharmacokinetic Valuesfor Amantadine HCl ER Tablets Administered Under Fed and FastingConditions, Study III Mean ± SD (Un-transformed data) Test-T2 Test-T1Parameters (Units) (under fed condition) (under fasting condition)T_(max) (h)* 9.009 (5.000-10.067) 9.000 (5.000-10.000) C_(max) (ng/mL) 726.500 ± 168.3258  667.406 ± 124.7239 AUC_(0-t) (ng · h/mL) 16689.043± 4142.8550 17736.805 ± 4550.6428 AUC_(0-∞) (ng · h/mL) 17379.367 ±4644.9896 18481.399 ± 5015.5387 λ_(z) (1/h)   0.053 ± 0.0113   0.053 ±0.0110 t½ (h)   13.564 ± 2.9835   13.577 ± 3.0546 AUC_%   3.509 ± 2.7670  3.625 ± 2.7349 Extrap_obs (%) T_(lag) (h)* 0.000 (0.000-0.667) 0.000(0.000-0.333) *T_(max) and T_(lag) are represented as median (min-max)value.

Conclusions

Amantadine bioavailability following oral administration of 320-mgAmantadine HCl ER Tablets under fed (Test) and fasted (Reference)conditions are equivalent. See mean profile in FIG. 1 for the relativebioavailability under fed and fasted conditions.

2.2.2 Study II (Relative Bioavailability of a Single Dose Amantadine HClER Tablets, 160 mg, 240 mg, and 320 mg Compared to Syrup Dose FormStudy)

Study II was a single center, randomized, laboratory-blinded,four-treatment, four-period, four-sequence, single oral dose crossoverdesign study in healthy male and female volunteers.

The primary study objectives were to evaluate dose proportionalitybetween Amantadine HCl ER Tablets, 160 mg, 240 mg, and 320 mg and todetermine the relative bioavailability of Amantadine HCl ER Tablets 160mg compared to a reference formulation of 160 mg of Amantadine HCl syrup(50 mg/5 mL) in healthy volunteers of both genders after single doseadministration under fasting conditions.

Subjects received the following treatments: Amantadine HCl 160-mg ERTablet (Treatment A), Amantadine HCl 240-mg ER Tablet (Treatment B),Amantadine HCl 320-mg ER Tablet (Treatment C), and 160 mg Amantadine HCl50 mg/5 mL syrup (Treatment D).

Following a 10-hour fast, subjects were orally administered theirassigned treatment with 240 mL water. During each treatment period, 28blood samples (4 mL each) were collected from each subject atpredetermined times, pre-dose and through 72 hours post-dose.

Results

As shown in FIG. 2 and Table 3, longer T_(max) and decreased C_(max)values confirmed slower rate of amantadine absorption from theAmantadine HCl ER Tablet; T_(max) occurred much later (approximately9.00 hours post dose) for the Amantadine HCl ER Tablet compared to 3.00hours for the oral amantadine HCl syrup; C_(max) value for the 160-mgAmantadine HCl ER Tablet was 81.05% of that following administration oforal syrup.

The extent of amantadine absorption from the 160-mg Amantadine HCl ERTablet was equivalent to that from 160 mg amantadine HCl syrup.

Plasma amantadine exposure (C_(max), AUC_(inf)) after single oral doses(160 mg, 240 mg, 320 mg) of Amantadine HCl ER Tablets increasedproportionally with increasing dose.

TABLE 3 Summary of Mean Pharmacokinetic Parameter Values (CV %) ofAmantadine Following Oral Administration of one 160 mg, 240 mg or 320 mgAmantadine HCl ER Tablet or 160 mg of Amantadine HCl Oral Syrup toFasted Healthy Volunteers, Study II Treatment A Treatment B Treatment CTreatment D PARAMETER (160 mg tablet) (240 mg tablet) (320 mg tablet)(160 mg syrup) (units) Mean (% CV) Mean (% CV) Mean (% CV) Mean (% CV)C_(max) (ng/mL) 328.21 (18.2) 459.56 (19.0) 629.52 (20.9) 403.54 (16.2)T_(max) (hours)^(a) 9.00 (5.50- 9.00 (6.00- 9.50 (5.00- 3.00 (1.50-10.00) 12.00) 12.00) 8.50) AUC_(0-T) 8263.28 (17.9) 12397.98 (17.6)16931.18 (19.9) 8686.33 (15.9) (ng · h/mL) AUC_(0-∞) 8580.45 (19.0)13123.64 (20.4) 17705.51 (21.3) 9007.72 (17.8) (ng · h/mL) λ_(Z)(hours⁻¹) 0.0524 (19.8) 0.0501 (28.1) 0.0515 (20.5) 0.0533 (22.2)T_(half) (hours) ^(b) 13.2 13.8 13.5 13.0 ^(a)Median (range), ^(b)harmonic mean T_(half) = 0.693/mean λ_(Z)

2.2.3 Study I (Relative Bioavailability of Amantadine HCl ER TabletsCompared to Amantadine HCl Syrup at Steady State)

Study I was a single center, laboratory-blinded, randomized,two-treatment, two-period, two-sequence, multiple oral dose crossoverdesign study with a two-day titration period in healthy male and femalevolunteers.

The primary objective of the study was to determine the steady-staterelative bioavailability after multiple dosing of Amantadine HCl ERTablets, 320 mg once a day compared to the plasma profiles andpharmacokinetics parameters of an equivalent daily dose of 320 mgAmantadine HCl Oral syrup (50 mg/5 mL) divided into two equal doses inhealthy volunteers of both genders under fasting conditions.

In each 9-day study period, a once daily dose of 160 mg amantadine HCloral syrup, 50 mg/5 mL (16 mL) was administered for 2 days (titrationperiod). Thereafter, 320 mg daily doses (one 320-mg Amantadine HCl ERTablet once daily [Treatment A]; or 160 mg amantadine HCl oral syruptwice daily [Treatment B]) were administered for 7 consecutive days.There was at least a 7-calendar day washout period between the lastmorning dose of the first period and the first dose of the secondperiod.

During each treatment period, 31 blood samples (4 mL each) werecollected from each subject, for pharmacokinetic analysis atpredetermined times: pre-dose and through 72 hours post-dose on Day 7.

Result: Following multiple-dose oral administration of 160-mg amantadineHCl syrup twice daily, plasma concentrations increased rapidly with amedian T_(max) value of 2.00 to 3.00 hours postdose (T_(max0-12) andT_(max12-24) was 3.00 and 14.00 hours, respectively) and thereafterdeclined in a log-linear manner with a terminal phase harmonic meanhalf-life of 13.7 hours, see FIGS. 3 and 4.

Following multiple-dose oral administration of Amantadine HCl ER 320-mgTablets once daily, amantadine plasma concentration increased slowlywith a median T_(max0-24) value of 7.50 hours and thereafter declined ina log-linear manner with a terminal phase harmonic mean half-life of13.3 hours, see FIGS. 3 and 4.

Longer T_(max) values confirmed slower rate of amantadine absorptionfrom Amantadine HCl ER Tablets; T_(max0-24) value was much later (7.50hours postdose) for Amantadine HCl ER Tablets compared to 2.00 to 3.00hours post dose for amantadine HCl oral syrup.

Both formulations achieved steady-state when evaluation was based on the−24, 0 and 24 hour concentrations for Day 7, thereby confirming thatsteady state was achieved by Day 6 (−24 hours). Mean 12-hour AUC valuesfollowing the morning (11656.41 ng h/mL) and evening (11506.74 ng h/mL)syrup doses on Day 7 were similar, further suggesting steady state wasachieved prior to Day 7.

At steady state, systemic exposure of amantadine from the once dailyAmantadine HCl ER Tablet was similar to the twice daily syrup, furthersupporting bioequivalence of the formulations.

The mean C_(avg) value for 320-mg Amantadine HCl ER Tablet administeredonce daily (947.40 ng/mL) was similar (98% to 99%) to the mean C_(avg)value of 160 mg amantadine HCl syrup administered in the morning (971.37ng/mL) and evening (958.90 ng/mL). The extent of amantadine absorptionfrom the once-daily Amantadine HCl ER Tablet as reflected by AUC₀₋₂₄ was97.48% of that of amantadine HCl syrup. Inspection of amantadine HClsyrup C_(max) values for each 12-hour dosing interval and for the24-hour sample interval revealed that C_(max) values for twice dailyadministration of 160-mg immediate-release amantadine HCl syrup, 50 mg/5mL were comparable to that for once daily administration of 320-mgAmantadine HCl ER Tablets, see Table 4.

The C_(min) value following oral administration of one Amantadine HCl ERTablet daily was slightly lower than that following twice dailyadministration of amantadine HCl syrup; the geometric least squares meanvalues were 565.68 and 695.90, respectively.

Bioequivalence

At steady state, the 320-mg Amantadine HCl ER Tablet is bioequivalent to320 mg/day amantadine HCl syrup (160 mg twice daily).

Conclusion

Amantadine is slowly absorbed from 320-mg Amantadine HCl ER Tablets.Steady state is achieved by the 6th day of multiple dose administrationof 320-mg Amantadine HCl ER Tablets once daily and 160 mg amantadine HCloral syrup, 50 mg/5 mL twice daily. At steady state, 320-mg AmantadineHCl ER Tablets are bioequivalent to 320 mg/day amantadine HCl oralsyrup, 50 mg/5 mL (160 mg administered twice daily).

TABLE 4 Mean Pharmacokinetic Parameter Values (CV %) of AmantadineFollowing Oral Administration of One 320-mg Amantadine HCl ER TabletDaily (Treatment-A) or 160 mg Amantadine HCl Oral Syrup Twice Daily(Treatment-B) to Fasted Healthy Volunteers, Study I Treatment-A^(a)Treatment-B^(b) PARAMETER MEAN C.V. (%) MEAN C.V. (%) C_(min0-12)(ng/mL) NC NC   747.53 (27.0) C_(min0-24) (ng/mL) 612.19 (39.5)   724.34(28.8) C_(max0-12) (ng/mL) NC NC  1129.02 (19.6) C_(max12-24) (ng/mL) NCNC  1140.03 (19.2) C_(max0-24) (ng/mL) 1275.01 (21.6)  1165.90 (18.9)T_(max0-12) (hours)^(c) NC NC    3.00 (2.00-7.50) T_(max12-24)(hours)^(c) NC NC   14.00^(e) (14.00-20.00) T_(max0-24) (hours)^(c) 7.50(5.00-11.95)   14.00^(e)  (2.00-20.00) AUC₀₋₁₂ (ng · h/mL) NC NC11656.41 (21.8) AUC₁₂₋₂₄ (ng · h/mL) NC NC 11506.74 (22.5) AUC₀₋₂₄ (ng ·h/mL) 22737.52 (24.7) 23163.15 (22.0) C_(avg0-12) (ng/mL) NC NC  971.37(21.8) C_(avg12-24) (ng/mL) NC NC  958.90 (22.5) C_(avg0-24) (ng/mL)947.40 (24.7)  965.13 (22.0) C_(pd (−48)) (ng/mL) 609.08 (36.5)  692.18(26.2) C_(d (−24)) (ng/mL) 662.28 (35.4)  750.17 (26.7) C_(pd (0))(ng/mL) 634.58 (39.6)  736.85 (27.8) C₂₄ (ng/mL) 662.70 (33.6)  762.75(29.8) λ_(z) (hours⁻¹) 0.0521 (27.6)   0.0505 (27.3) T_(half)(hours)^(d) 13.3 NA   13.7 NA NA = not applicable; NC = not calculated^(a)Treatment-A = Amantadine HCl 320 mg ER tablet once daily^(b)Treatment-B = Amantadine HCl 160 mg dose oral solution twice daily,50 mg/5 mL ^(c)Median (range) ^(d)harmonic mean half-life (T_(half) =0.693/mean λ_(z)) ^(e)14.00 hours is 2.00 h postdose

Example 3 In Vitro Dissolution

Amantadine HCl ER Tablets were analyzed in various media to confirm theextended release of amantadine HCl from Amantadine HCl ER Tablets. ThreeAmantadine HCl ER Tablets were manufactured as described in Example 1and the dissolution profile data are presented in FIGS. 5-7. Thedissolution profiles of extended release cores for each of the threestrengths (160 mg, 240 mg, and 320 mg) have also been characterized inthe following four dissolution media: 1) water (drug product testmethod) 2) 0.1 N HCl, 3) pH 4.5 acetate buffer and 4) pH 6.8 phosphatebuffer.

All 3 strengths (160 mg, 240 mg, and 320 mg of amantadine HCl) aresoluble in 250 mL water, and sink conditions (concentration is less than20% of solubility of amantadine HCl).

3.1 Dissolution in Water

The dissolution test method for Amantadine HCl ER Tablets is summarizedin Table 5.

In vitro dissolution data revealed slow release of amantadine HCl fromAmantadine HCl ER Tablets, 160 mg, 240 mg and 320 mg. Slow release ofamantadine HCl from Amantadine HCl ER Tablets was reflected in therelatively long T_(max) values (9 hours) in the bioavailability studieswhich confirmed slow absorption of amantadine after oral administrationof Amantadine HCl ER Tablets, 160 mg, 240 mg and 320 mg.

TABLE 5 Summary of Dissolution Test Method for Amantadine HCl ERTablets, 160 mg, 240 mg and 320 mg Apparatus USP Apparatus 2 PaddlesTemperature 37.0 ± 0.5° C. Speed 50 rpm Volume 900 mL Dissolution mediumPurified water Draw volume 9 mL Offset¹ 3 mL Flush time¹ 1 time Flushvolume¹ 10 mL (recycle Option-ON) Pull times 0.5 hour, 2.5 hour, 4 hour,and 8 hour Analytical method HPLC Test method reference AP-0057¹Auto-sampler parameters for Distek Evolution 4300 DissolutionAuto-sampler.

A summary of the dissolution profiles for the amantadine extendedrelease tablet cores in water is shown in Table 6.

TABLE 6 Summary of Dissolution of the Extended Release Core ofAmantadine HCl ER Tablets, 160 mg, 240 mg and 320 mg Strength 320 mg %Dissolved at Time   1 h  3  9  6  5 (Hr) (1-4)¹ (4-10) (5-8) (2-7) Mean2.5 h 27 43 43 39 (Min-Max) (21-36)¹ (31-55) (40-47) (29-46)   4 h 55 6768 66 (47-63)¹ (56-78) (66-71) (58-71)   6 h 79 86 88 88 (73-85)¹(80-93) (87-91) (83-91)   8 h 92 94 96 95 (88-94)¹ (91-97) (95-97)(94-98) 240 mg % Dissolved at Time   1 h  1  2  1  1 (Hr) (0-3)  (1-5)¹(1-3) (0-2) Mean 2.5 h 16 23 23 22 (Min-Max)  (5-32) (13-45)¹ (12-36)(11-31)   4 h 54 54 56 55 (43-71) (45-73)¹ (45-67) (42-63)   6 h 85 8284 84 (76-92) (76-91)¹ (77-91) (75-88)   8 h 96 92 93 94 (99-92)(89-97)¹ (91-96) (91-97) 160 mg % Dissolved at Time   1 h 1 2 3 (Hr)(0-3) (1-3) (2-8) Mean 2.5 h 25 24 31 (Min-Max)  (8-40) (13-34) (18-56)  4 h 65 62 68 (54-74) (49-72) (60-86)   6 h 90 89 91 (86-93) (84-91)(88-96)   8 h 96 96 97 (95-98) (95-97) (95-99) ¹Did not meet dissolutioncriteria.

3.2 Dissolution in Various Media

The effect of dissolution media on drug release from Amantadine HCl ERTablets was also examined. A comparison of the profiles by strength isprovided in FIG. 5 through FIG. 7. As expected, the dissolution profileof these osmotic pump tablets is relatively insensitive to thedissolution media. The dissolution profiles were comparable (f₂>50) inwater vs 0.1 N HCl and pH 4.5 buffer. The profiles were also comparablein 0.1 N HCl vs pH 6.8 buffer, but they were not considered comparable(f₂<50) in water or pH 4.5 vs pH 6.8.

The dissolution profile of Amantadine HCl ER Tablets, 160 mg, 240 mg and320 mg in water (QC dissolution medium) for each of the threeregistration batches was similar with each other.

After release of the 60-mg immediate-release portion of the tablet, therelease rate of amantadine HCl from Amantadine HCl ER Tablets in 0.1 NHCl, pH 4.5 acetate buffer, or pH 6.8 phosphate buffer was similar forall three strengths.

The dissolution of these osmotic pump tablets is relatively insensitiveto the dissolution media.

3.3 Ethanol Dissolution

In vitro drug dissolution studies (using 12 tablets) were conduct toevaluate the potential of alcohol induced dose dumping. Drug release forall product strengths at ethanol levels of 0%, 5%, 20% and 40% in 0.1NHCl (pH 1.2) and in water (media of the drug product [QC] dissolutionmethod) were measured employing the chromatographic parameters. Table 5.

3.3.1 Ethanol Impact on Amantadine HCl Immediate-Release Portion

All tablet strengths contained 60 mg amantadine HCl in an IR layer whichwas coated onto the extended-release tablet core; 60 mg is 38%, 25% and19% of the label claim (LC) for the 160-mg, 240-mg and 320-mg ERtablets, respectively. The amount of ethanol in water or 0.1N HCl didnot affect the amount released in 30 minutes for any of the strengths;mean amount released values ranged from 53 to 70 mg amantadine HCl.

3.3.2 Impact on Extended Release Properties 3.3.2.1 160 mg ER Tablets

As shown in, FIG. 8 and FIG. 9, levels of ethanol up to 20% in acidicand QC media did not affect the release profile of the 160-mg tablets,f₂ values were greater than 50, see Table 7.

TABLE 7 Summary of Comparison of Amantadine HCl Dissolution Profiles for160-mg Amantadine HCl ER Tablets in Acidic (0.1N HCl) or QC (Water)Media Containing 0%, 5%, 20% and 40% Ethanol f₂ Amount dissolved Amountdissolved (% Dissolution Media value (mg) in 2 hours LC) in 2 hours  0%EtOH/0.1N HCl NA  69 mg 43%  5% EtOH/0.1N HCl 90  70 mg 44% 20%EtOH/0.1N HCl 65  83 mg 52% 40% EtOH/0.1N HCl 46 101 mg 63%  0%EtOH/water NA  69 mg 43%  5% EtOH/water 77  77 mg 48% 20% EtOH/water 57 90 mg 56% 40% EtOH/water 42 106 mg 66%

Compared to 0% ethanol, the amount released over the 2-hour period in40% ethanol increased by only 32 mg and 37 mg in 0.1 N HCl and water,respectively (32% and 37% of the 100 mg amantadine HCl in theextended-release tablet core of 160-mg ER tablet). Inspection of thedissolution profiles revealed that the Amantadine HCl ER 160-mg Tabletsmaintained their extended-release properties. The profile maintained itspseudo-zero order characteristic; the release profile was linear from 30minutes to 120 minutes. Moreover, the maximum amount released in 2 hourswas only 101 mg or 106 mg amantadine HCl, approximately one-half of anamantadine HCl oral solution dose of 200 mg.

These results confirm that Amantadine HCl ER 160-mg Tablets do not dosedump in ethanol solutions containing up to 40% ethanol, as shown inTable 8 and Table 9.

TABLE 8 160-mg Amantadine HCl ER Tablets—Mean Amount Amantadine HClReleased in 0.1N HCl and 0%, 5%, 20% and 40% Ethanol Over a Two-HourPeriod % Ethanol 15 min 30 min 45 min 60 min 75 min 90 min 105 min 120min Mean Amount Released (% Label Claim) by Sample Time (minutes) 0 3538 38 38 39 40 41 43 5 33 36 37 37 38 40 42 44 20 32 35 37 39 41 45 4952 40 30 35 39 45 50 55 59 63 Mean Amount Released (mg) by Sample Time(minutes) 0 56 61 61 61 62 64 66 69 5 53 58 59 59 61 64 67 70 20 51 5659 62 66 72 78 83 40 48 56 62 72 80 88 94 101

TABLE 9 160-mg Amantadine HCl ER Tablets—Mean Amount Amantadine HClReleased in Water and 0%, 5%, 20% and 40% Ethanol Over a Two-Hour Period% Ethanol 15 min 30 min 45 min 60 min 75 min 90 min 105 min 120 min MeanAmount Released (% Label Claim) by Sample Time (minutes) 0 34 36 36 3738 39 41 43 5 35 38 38 39 40 42 44 48 20 31 35 37 40 43 47 52 56 40 3035 41 47 52 58 62 66 Mean Amount Released (mg) by Sample Time (minutes)0 54 58 58 59 61 62 66 69 5 56 61 61 62 64 67 70 77 20 50 56 59 64 69 7583 90 40 48 56 66 75 83 93 99 106

Characterization of the profile for 8 hours was performed for the 160-mgtablets. The impact of ethanol on the dissolution profile was examinedfurther for the 160-mg Amantadine HCl ER Tablets as this strength wasaffected the most in the 2-hour studies. FIG. 10 and FIG. 11 includedata from both the 2-hour and 8-hour alcohol interaction studies, andshow that levels of ethanol up to 20% in both acidic and QC media didnot affect the release profile of the 160-mg tablets over the 8 hourperiod, f₂ values were greater than 50. In 40% ethanol, the f₂ valueswere below 50 for both the acidic (f₂=43) and QC media (f₂=46), butinspection of the dissolution profiles and the amount of amantadine HClreleased confirm that the Amantadine HCl ER 160-mg Tablets do not dosedump in ethanol solutions containing up to 40% ethanol.

3.3.2.2 240 mg ER Tablets

The dissolution study of 240 mg ER Tablets was conducted using the sametest method as shown in Table 5 and in the same media as 160 mg ERtablets. FIG. 12 and FIG. 13 show the result of the dissolution study.These results confirmed that Amantadine HCl ER 240-mg tablets, similarto the 160 mg tablets, do not dose dump in ethanol solutions containingup to 40% ethanol.

3.3.2.3 320 mg ER Tablets

The dissolution study of 320 mg ER Tablets was conducted using the sametest method as shown in Table 5 and in the same media as 160 mg ERtablets. FIG. 14 and FIG. 15 show the result of the dissolution study.These results confirmed that the Amantadine HCl ER 320-mg tablets,similar to the 160 mg tablets, do not dose dump in ethanol solutionscontaining up to 40% ethanol.

3.3.3 Conclusions

Examination of amantadine HCl dissolution profiles in 40% ethanol inacidic (0.1 N HCl) or QC (water) media revealed that Amantadine HCl ER160-mg, 240-mg, and 320-mg tablets maintained their extended-releaseproperties. The profile maintained its pseudo-zero order characteristic;the release profile was linear from 30 minutes to 120 minutes. Themaximum increase in amantadine HCl release induced by the addition of upto 40% ethanol was only 37%, 34% and 16% of the amount of amantadine HClin the extended release tablet core for the 160-mg, 240-mg and 320-mg ERTablets, respectively. Moreover, the maximum amount released in 2 hoursfor the 160-mg, 240-mg and 320-mg ER Tablets was only 53%, 66% and 87%of the dose of a 200-mg immediate-release amantadine HCl oral solutiondose.

Further examination of amantadine HCl dissolution profiles for 160-mgAmantadine HCl ER Tablets in up to 40% ethanol for 8 hours confirmed theabsence of dose dumping.

Dissolution media containing up to 40% ethanol does not compromise therelease-rate controlling mechanism of the extended-release tablet coreof Amantadine HCl ER Tablets. Amantadine HCl ER Tablets do not dose dumpin ethanol solutions containing up to 40% ethanol.

Example 4 Study to Confirm Extended Release for Amantadine HCl ERTablets

Amantadine HCl immediate-release products (tablet, capsule, syrup(solution)) are administered twice daily. Amantadine HCl ER Tablets havebeen developed for once daily administration. All three strengths (160mg, 240 mg, and 320 mg) of Amantadine HCl ER Tablets provide 60 mg as animmediate-release dose, and the remainder of the amantadine HCl dose iscontained in the extended-release tablet core.

In vitro dissolution studies confirm that amantadine HCl is slowlyreleased over 8 hours from Amantadine HCl ER Tablets, see FIGS. 5-7.

The 3 bioavailability studies in Example 2 were also conducted tofurther characterize the extended-release properties of Amantadine HClER Tablets.

The reference material for these bioavailability studies was AmantadineHCl Oral Syrup, 50 mg/5 mL, an approved drug product solution, of theactive ingredient (amantadine HCl).

Longer T_(max) values in Study II revealed that amantadine is slowlyabsorbed following single oral dose administration of Amantadine HCl ERTablets, 160 mg, 240 mg or 320 mg. Amantadine plasma exposure (C_(max),AUC_(0-∞)) increased dose proportionally following oral administrationof single doses of 160-mg, 240-mg, and 320-mg Amantadine HCl ER Tablets.The extent of amantadine absorption (AUC) from the 160-mg ER tablet isequivalent to that from 160 mg Amantadine HCl Oral Syrup, 50 mg/5 mL.

Furthermore, following multiple-dose, once-daily, steady stateadministration in Study I, Amantadine HCl ER Tablets 320 mg werebioequivalent to 320 mg Amantadine HCl Oral Syrup (160 mg twice daily).Thereby confirming that the drug product's steady-state performance isequivalent to a currently marketed non-extended-release drug productthat contains the same active drug ingredient or therapeutic moiety andthat is subject to an approved full new drug application. Inspection ofindividual and mean subject data following once-daily oraladministration of Amantadine HCl ER Tablets for 7 days revealed that theamantadine plasma concentration values 24 hours after dose 5, 6 and 7administration were consistent, see FIG. 16.

Study III revealed that amantadine bioavailability following oraladministration of 320-mg Amantadine HCl ER Tablets with a high fat meal(fed, Test) is equivalent to fasted (Reference). No significant foodeffect was observed, thereby ruling out the occurrence of any dosedumping.

Example 5 Pharmacokinetics

Four different formulations were used in this example: 160 mg amantadineHCl syrup (50 mg of amantadine HCl/5 ml, administered 16 ml), inimmediate release form; and Amantadine ER 160, 240, 320 mg tablets,manufactured as described in Example 1.

5.1 Absorption, Distribution, and Elimination Absorption

Following oral administration of Amantadine ER, the peak concentrationof amantadine was observed in a median time of 7.5 hours (range 5.5 to12 hours). After a single oral administration of the Amantadine ER 160mg tablet (129 mg dose in terms of amantadine freebase), the mean (CV %)Cmax and AUC were 328 ng/ml (18%) and 8263 ng·h/ml (18%) respectively.Cmax and AUC with other dose levels of Amantadine ER increaseproportionally.

Effect of Food

Food does not affect the rate or the extent of absorption of AmantadineER.

Distribution

Amantadine is 67% bound to plasma proteins over a concentration range of0.1 to 2.0 μg/mL. The volume of distribution after intravenousadministration is 3-8 L/kg, suggesting potential extravasculardistribution.

Elimination

Amantadine is mainly eliminated renally, and approximately 85% of theadministered dose is excreted unchanged in urine. After oraladministration of a single Amantadine ER 160 mg tablet (129 mg dose interms of amantadine free base), the apparent oral clearance wasapproximately 11 L/h. The half-life was approximately 16 hours.Coadministration of quinine or quinidine with amantadine was shown toreduce the renal clearance of amantadine by about 30%.

Metabolism

Metabolism accounts for only 5-15% of the total clearance foramantadine. Eight metabolites of amantadine have been identified inhuman urine. One metabolite, an N-acetylated compound, was quantified inhuman urine and accounted for 0-15% of the administered dose in multiplestudies. The contribution of this metabolite to efficacy or toxicity isnot known.

Excretion

Amantadine is primarily excreted by glomerular filtration and tubularsecretion. The pH of the urine has been reported to influence theexcretion rate of amantadine.

5.2 Steady State Pharmacokinetic Simulations

Using the formulations described above, the amantadine plasmaconcentration over a period of 24 hours was simulated using thepharmacokinetic software, NONMEM 7, PDx-POP 5.2 following theadministration of either 200 mg amantadine in an immediate releaseformulation b.i.d. (twice per day) or 400 mg amantadine in a sustainedrelease formulation q.d. (160 mg tablet+240 tablet administeredsimultaneously, once per day). As shown in FIG. 17, the initial slope ofthe dC/dT for the sustained release formulation is less than the slopedetermined for the immediate release formulation. As shown in FIG. 17and Table 10, the sustained release formulation exhibits slightly higherplasma concentration peaks and longer T_(max) and T_(last) compared withthe immediate release formulation. In addition, the sustained releaseformulation indicates higher exposures (AUC_(0-τ)) compared with theimmediate release formulation.

TABLE 10 Amantadine steady state pharmacokinetic parameters Dose C_(max)T_(max) T_(last) C_(last) AUC_(0-τ) cav TMT Regimen ng/mL h h ng/mL hng/mL ng/mL ER 160 mg + 1532 7.5 24 857 28838 1202 240 mg q24 h IR 200mg q12 h 1342 3 12 1002 14413 1201

Example 6 Pharmacokinetics in Special Populations 6.1 Effect of Age

The apparent oral plasma clearance of amantadine is reduced, and theplasma half-life and plasma concentrations are increased in healthyelderly individuals age 60 and older. After single dose administrationof 25 to 75 mg to 7 healthy, elderly male volunteers, the apparentplasma clearance of amantadine was 0.10±0.04 L/h/kg (range 0.06 to 0.17L/h/kg) and the half-life was 29±7 hours (range 20 to 41 hours). Whetherthese changes are due to decline in renal function or other age relatedfactors is not known.

In clinical studies with Amantadine ER tablets, patients 65 to 85 yearsof age on average had higher plasma amantadine concentrations thanyounger patients.

6.2 Effect of Gender

In a study of young healthy subjects (n=20), mean renal clearance ofamantadine, normalized for body mass index, was 1.5 fold higher in malescompared to females (p<0.032).

6.3 Effect of Renal Impairment

Compared with otherwise healthy adult individuals, the clearance ofamantadine is significantly reduced in adult patients with renalinsufficiency. The elimination half-life increases two to three fold orgreater when creatinine clearance is less than 40 mL/min/1.73 m² andaverages eight days in patients on chronic maintenance hemodialysis.Amantadine is removed in negligible amounts by hemodialysis.

Renal Impairment—Amantadine ER

A summary of plasma C_(max), T_(max), AUC_(0-∞), terminal eliminationhalf-life (T-half), apparent clearance (CL/F), and apparent volume ofdistribution (Vd/F) following a single 160-mg dose of Amantadine ER insubjects with normal renal function compared with subjects with moderateand severe renal impairment is provided in Table 11.

TABLE 11 Summary of Amantadine ER Pharmacokinetic Parameters in Patientswith Renal Impairment and Control Subjects with Normal Renal FunctionC_(max) T_(max) AUC_((0-0-∞)) T-half CL/F Vd/F (ng/mL) (h) (ng · h/mL)(h) (L/h) (L) Mean Median Mean Mean Mean Mean Renal Function (% CV)(range) (% CV) (% CV) (% CV) (% CV) Moderate Impairment¹ N  8  8   8  8 8  8 eGFR 30-59 mL/min/1.73 380.0 11.5 33066.1  47.2  5.5 344.8 m²(21.4) (9.0-24.0) (31.6) (31.4) (45.2) (26.5) Severe Impairment¹ N  8  8  8  8  8  8 eGFR < 30 mL/min/1.73 344.9 11.0 39031.7 116.3  4.6 799.8m² (22.8) (6.0-14.0) (39.9) (46.6) (29.9) (68.8) Normal² N  8  8   8  8 8  8 CrCl > 89 mL/min 281.3 11.0 10108.7  18.5 17.4 448.2 (26.4)(8.0-12.2) (26.9) (13.2) (40.3) (27.3) ¹eGFR estimated by theModification of Diet in Renal Disease equation ²CrCl estimated by theCockcroft-Gault equation

The mean renal amantadine clearance was 11 L/h (% CV 41.3), 3.5 L/h (%CV 47.0), and 2.6 L/h (% CV 34.5) in subjects with normal renalfunction, moderate, and severe renal impairment, respectively.

Dosing in Patients with Renal Impairment

There are no modifications for the recommended initial and maximumdosage in patients with renal impairment; however, modifications arecontemplated for the titration interval and frequency of dosing inpatients with moderate and severe renal impairment. Renal Function isestimated by Modification of Diet in Renal Disease (MDRD) method,expressed as Estimated GFR (mL/min/1.73 m²). For Mild renal impairment(60 to 89), the minimum titration interval is to increase every week andfrequency of dosing regimen is one dose every 24 hours. For Moderaterenal impairment (30 to 59), the minimum titration interval is toincrease every 3 weeks and frequency of dosing regimen is one dose every48 hours. For Severe renal impairment (15 to 29), the minimum titrationinterval is to increase every 4 weeks and frequency of dosing regimen isone dose every 96 hours. For End-Stage renal impairment (below 15),minimum titration interval and frequency of dosing regimen iscontraindicated. It is recommended to monitor patients with renalimpairment for change in renal function, especially in those with severerenal impairment receiving the maximum daily dosage of 322 mg.

Example 7 Clinical Studies: Primary and Secondary Efficacy Analysis

Amantadine HCl ER Tablets as described in Example 1 were used in Phase 3clinical studies.

7.1 Overview

Two randomized, double-blind, placebo-controlled Phase 3 studies (StudyA and Study B) evaluated the efficacy and safety of Amantadine HCl ERTablets at dosages of 240 mg/day and 320 mg/day for the treatment ofParkinson's disease (PD) patients with LID.

7.2 Study Designs—Phase 3 Clinical Studies Study A

Study A was a Phase 3, randomized, double-blind, placebo-controlled,parallel-group, 3-arm, multicenter study. This was a fixed-dose trial(after a Titration Period) that compared the efficacy and safety ofAmantadine HCl ER tablets with placebo in subjects 30 to 85 years of agewith PD who had LID. Subjects diagnosed with secondary PD or had ahistory of pallidotomy or other ablative surgery for treatment of PD, orhad been implanted with a uni- or bilateral deep brain stimulator, wereexcluded from participation in the study.

Eligible subjects were randomized in a 1:1:1 manner into one of threetreatment groups: Amantadine HCl ER 320 mg, Amantadine HCl ER 240 mg, orPlacebo.

Subjects assigned to the Amantadine HCl ER 320 mg group underwent a2-week dose titration beginning with a 160 mg QD dose for 1 week, then a240 mg QD dose for 1 week, and then a 320 mg QD dose for 12 weeksfollowed by a dose-taper for 2 weeks. Subjects assigned to theAmantadine HCl ER 240 mg group underwent a 2-week dose titrationbeginning with placebo QD dose for 1 week, then a 160 mg QD dose for 1week, and then a 240 mg QD dose for 12 weeks followed by a dose-taperfor 2 weeks. Subjects assigned to the Placebo group took placebo tabletsQD for 16 weeks.

Study B

Study B was a Phase 3, randomized, double-blind, placebo-controlled,parallel-group, 3-arm, multicenter study. This was a fixed-dose trial(after a Titration Period) that compared the efficacy and safety ofAmantadine HCl ER tablets with placebo in subjects 30 to 85 years of agewith PD who had LID. Subjects diagnosed with secondary PD or had ahistory of pallidotomy or other ablative surgery for treatment of PD, orhad been implanted with a uni- or bilateral deep brain stimulator wereexcluded from participation.

Eligible subjects were randomized in a 1:1:1 manner into one of threetreatment groups: Amantadine HCl ER 320 mg, amantadine HCl ER 240 mg, orPlacebo.

Subjects assigned to the Amantadine HCl ER 320 mg group underwent a2-week dose titration beginning with a 160 mg QD (every day) dose for 1week, then a 240 mg QD dose for 1 week, and then a 320 mg QD dose for 22weeks followed by a dose-taper for 2 weeks. Subjects assigned to theAmantadine HCl ER 240 mg group underwent a 2-week dose titrationbeginning with placebo QD dose for 1 week, then a 160 mg QD dose for 1week, and then a 240 mg QD dose for 22 weeks followed by a dose-taperfor 2 weeks. Subjects assigned to the Placebo group took placebo tabletsQD for 26 weeks.

Study A and Study B were almost identical; the primary differencebetween the two studies was the duration of treatment. The duration oftreatment was 16 and 26 weeks for Study A and Study B, respectively.

Unified Dyskinesia Rating Scale (UDysRS)

Overview: The Unified Dyskinesia Rating Scale (UDysRS) is developed toevaluate involuntary movements often associated with treatingParkinson's disease. There are two primary sections:

On-Dyskinesia refers to the choreic and dystonic movements described tothe patient as “jerking or twisting movements that occur when yourmedicine is working.”

Off-Dystonia were described to the patient as “spasms or cramps that canbe painful and occur when your Parkinson's disease medications are nottaken or are not working.”

7.3 Efficacy Results—Pooled Analysis of Phase 3 Studies (Study A andStudy B)

Table 12 summarizes subject disposition for the Phase 3 StudyPopulation. The Phase 3 Study Population included subjects from the twoPhase 3 studies (Study A and Study B).

TABLE 12 Subject Disposition by Treatment Group-Study A and StudyB-Phase 3 Study Population Amantadine Amantadine All HCl ER HCl ER 240Subjects 320 mg mg Placebo Combined n (%) n (%) n (%) n (%) Screened 348Randomized Population 75 75 72 222 ITT Population 75 (100.0) 75 (100.0)72 (100.0) 222 (100.0) Completed the Study 46 (61.3) 44 (58.7) 43 (59.7)133 (59.9) Discontinued Study by Reason 29 (38.7) 31 (41.3) 29 (40.3) 89 (40.1) Adverse Event 13 (17.3)  8 (10.7)  6 (8.3)  27 (12.2) Lack ofEfficacy  0 (0.0)  0 (0.0)  1 (1.4)  1 (0.5) Lost to Follow-up  0 (0.0) 0 (0.0)  1 (1.4)  1 (0.5) Non-Compliance with Study Drug  0 (0.0)  0(0.0)  1 (1.4)  1 (0.5) Physician Decision  0 (0.0)  2 (2.7)  1 (1.4)  3(1.4) Protocol Violation  1 (1.3)  2 (2.7)  1 (1.4)  4 (1.8) TrialScreen Failure*  0 (0.0)  0 (0.0)  1 (1.4)  1 (0.5) Study Terminated bySponsor  8 (10.7) 11 (14.7)  8 (11.1)  27 (12.2) Withdrawal by Subject 6 (8.0)  8 (10.7)  8 (11.1)  22 (9.9) Other  1 (1.3)  0 (0.0)  1 (1.4) 2 (0.9) The denominator for calculating percentages is the number ofsubjects in the Randomized Population. *Subject 002-003 was randomizedto study A in error with high serum creatinine levels. As the subjectneared completion of the study, the high serum creatinine levels werenoted and the investigator removed the subject from the study on StudyDay 139 with the reason for discontinuation recorded as “trial screenfailure”. ER = extended-release; ITT = Intention-to-Treat.

Table 13 presents the results for mean change in Total UDysRS score frombaseline to Day 98 (Visit 7) using stable dose LOCF for the Phase 3Intent To Treat (“ITT”) Population. The mean reduction from baseline toDay 98 using stable dose LOCF was 13.5 for the Amantadine HCl ER 320 mggroup, 16.5 for the Amantadine HCl ER 240 mg group, and 9.3 for thePlacebo group.

TABLE 13 Mean Change in Total UDysRS Score from Baseline to Day 98 UsingStable Dose LOCF-Study A and Study B-Phase 3 ITT Population AmantadineHCl Amantadine HCl Visit ER 320 mg ER 240 mg Placebo Statistic (N = 75)(N = 75) (N = 72) Visit 2 (Baseline) n 74 74 72 Mean (SD)   37.4 (12.21)  43.3 (13.74)   39.9 (12.94) Visit 7 (Day 98)/Stable Dose LOCF [1] n 6666 62 Mean (SD)   24.0 (13.03)   26.9 (15.89)   30.3 (13.19) Change from−13.5 (11.88) −16.5 (15.86)  −9.3 (12.39) Baseline (SD) The analysisvisit window for Day 98 (Visit 7) for the primary endpoint used stabledose last observation carried forward (last data point collected afterDay 39 and before Day 102). n is the number of subjects with values ateach time point. ER = extended-release; LOCF = last observation carriedforward; SD = standard deviation; UDysRS = Unified Dyskinesia RatingScale.

Table 14 presents the treatment comparisons of the Amantadine HCl ER 320mg group and the Amantadine HCl ER 240 mg group with placebo for meanchange in Total UDysRS score from baseline to Day 98 using stable doseLOCF for the Phase 3 ITT Population. Treatment with Amantadine HCl ER320 mg resulted in a significantly larger reduction in Total UDysRSscore than placebo (−5.2; p=0.017). Treatment with Amantadine HCl ER 240mg also resulted in a significantly larger reduction in Total UDysRSscore than placebo (−5.5; p=0.012).

TABLE 14 Analysis of Mean Change in Total UDysRS Score from Baseline toDay 98 Using Stable Dose LOCF- Studies A and B-Phase 3 ITT PopulationTreatment Difference (Amantadine HCl ER vs. Placebo) LS 95% CI ofTreatment Group Mean (SE) Difference Difference P-value Amantadine HCl−14.7 (1.51) −5.2 (−9.5, −0.9) 0.017 ER 320 mg Amantadine HCl −15.1(1.52) −5.5 (−9.8, −1.2) 0.012 ER 240 mg Placebo  −9.5 (1.55)

7.5.4 Secondary Efficacy Analysis—Change in the Number of Awake “ON”Hours Without Troublesome Dyskinesias from Baseline to Day 98 UsingStable Dose LOCF

Table 15 presents the results for mean change in number of awake “ON”hours without troublesome dyskinesia (without dyskinesia and withnon-troublesome dyskinesia) from baseline to Day 98 using stable doseLOCF for the Phase 3 ITT Population.

The mean increase from baseline to Day 98 using stable dose LOCF was 3.7hours for the Amantadine HCl ER 320 mg group, 2.3 hours for theAmantadine HCl ER 240 mg group, and 1.5 hours for the Placebo group.

TABLE 15 Mean Change in Number of Awake “ON” Hours Without TroublesomeDyskinesias from Baseline to Day 98 Using Stable Dose LOCF- Study A andStudy B-Phase 3 ITT Population Visit Amantadine HCl Amantadine HClStatistic ER 320 mg ER 240 mg Placebo Visit 2 (Baseline) n 72 72 62 Mean(SD)  9.7 (3.48) 10.0 (3.73)  9.5 (3.51) Visit 7 (Day 98)/Stable DoseLOCF [1] n 75 75 72 Mean (SD) 13.5 (4.50) 12.2 (4.04) 11.3 (3.66) Changefrom  3.7 (4.40)  2.3 (3.47)  1.5 (3.49) Baseline (SD) The analysisvisit window for Day 98 (Visit 7) for the secondary endpoint used stabledose last observation carried forward (last data point collected afterDay 39 and before Day 102). n is the number of subjects with values ateach time point.

Table 16 presents the treatment comparisons of the Amantadine HCl ER 320mg group and the Amantadine HCl ER 240 mg group with placebo for meanchange in number of awake “ON” hours without troublesome dyskinesia frombaseline to Day 98 using stable dose LOCF for the Phase 3 ITTPopulation.

Treatment with Amantadine HCl ER 320 mg resulted in a significantlylarger increase in number of awake “ON” hours without troublesomedyskinesia than placebo (2.3 hours; p<0.001). The treatment comparisonof Amantadine HCl ER 240 mg with placebo was not statisticallysignificant (p=0.119).

TABLE 16 Analysis of Mean Change in Number of Awake “ON” Hours WithoutTroublesome Dyskinesias from Baseline to Day 98 Using Stable DoseLOCF-Study A and Study B-Phase 3 ITT Population Treatment Difference(Amantadine HCl ER vs. Placebo) 95% CI of Treatment Group LS Mean (SE)Difference Difference P-value Amantadine HCl 3.67 (0.42) 2.3 (1.1, 3.5)<0.001 ER 320 mg Amantadine HCl 2.36 (0.42) 1.0 (−0.3, 2.2) 0.119 ER 240mg Placebo 1.39 (0.45)

7.5.5 Exploratory Efficacy Analyses 7.5.5.1 Change in the Number ofAwake “OFF” Hours from Baseline to Day 98 Using Stable Dose LOCF

Table 17 presents the results for mean change in number of awake “OFF”hours from baseline to Day 98 using stable dose LOCF for the Phase 3 ITTPopulation. The changes in awake “OFF” hours over time for all treatmentgroups were small with no meaningful trends observed.

TABLE 17 Number of Awake “OFF” Hours from Baseline to Day 98 UsingStable Dose LOCF-Study A and Study B-Phase 3 ITT Population VisitAmantadine HCl Amantadine HCl Statistic ER 320 mg ER 240 mg PlaceboVisit 2 (Baseline) n 68 68 58 Mean (SD)   3.7 (2.45) 3.4 (2.03)   4.2(2.11) Visit 7 (Day 98)/ Stable Dose LOCF [1] n 72 74 69 Mean (SD)   3.4(2.45) 3.6 (2.36)   3.7 (2.05) Change from −0.3 (2.12) 0.3 (2.34) −0.3(2.25) Baseline (SD) The analysis visit window for Day 98 (Visit 7) forthe primary endpoint used stable dose last observation carried forward(last data point collected after Day 39 and before Day 102). n is thenumber of subjects with values at each time point.

Table 18 presents the treatment comparisons of the Amantadine HCl ER 320mg group and the Amantadine HCl ER 240 mg group with placebo for meanchange in number of awake “OFF” hours from baseline to Day 98 usingstable dose LOCF for the Phase 3 ITT Population. No statisticallysignificant treatment differences were observed.

TABLE 18 Analysis of Mean Change in Number of Awake “OFF” Hours fromBaseline to Day 98 Using Stable Dose LOCF-Study A and Study B-Phase 3ITT Population Treatment Difference (Amantadine HCl ER vs. Placebo) 95%CI of Treatment Group LS Mean (SE) Difference Difference P-valueAmantadine HCl −0.29 (0.244) −0.26 (−0.97, 0.45) 0.472 ER 320 mgAmantadine HCl   0.12 (0.245)   0.15 (−0.57, 0.87) 0.680 ER 240 mgPlacebo −0.03 (0.266)

7.5.5.2 Change in the Sum of MDS-UPDRS Parts II and III from Baseline toDay 98 Using Stable Dose LOCF

The MDS-UPDRS is a validated scale used to evaluate differentneurological aspects of parkinsonian subjects and is composed of 4parts: Part I (non-motor experiences of daily living), Part II (motorexperiences of daily living), Part III (motor examination) and Part IV(motor complications). The MDS-UPDRS Parts II and III were completed atscreening (Visit 1), at baseline (Visit 2), at the end of the TitrationPeriod (Visit 4), during the Maintenance Period (Visits 5, 6, and 7) orat the Premature Termination Visit.

The MDS-UPDRS Part II score and the MDS-UPDRS Part III score werederived. The MDS-UPDRS Part II score was calculated as the sum of theindividual scores for Part II (score range is from 0 to 52). TheMDS-UPDRS Part III score was calculated as the sum of the 33 individualscores for Part III (score range is from 0 to 132).

For the integrated/pooled analysis, the change from baseline in the sumof MDS-UPDRS Part II and Part III score was analyzed at Day 98 (Visit7).

Table 19 presents the results for mean change in the sum of MDS-UPDRSParts II and III from baseline to Day 98 using stable dose LOCF for thePhase 3 ITT Population. The mean change in the sum of MDS-UPDRS Parts IIand III was −4.3 for the Amantadine HCl ER 320 mg group, −5.9 for theAmantadine HCl ER 240 mg group, and −8.3 for the Placebo group.

TABLE 19 Mean Change in the Sum of MDS-UPDRS Parts II and III fromBaseline to Day 98 Using Stable Dose LOCF-Study A and Study B-Phase 3ITT Population Visit Amantadine HCl ER Amantadine HCl ER Statistic 320mg 240 mg Placebo Visit 2 (Baseline) n 75 75 72 Mean (SD)   37.3 (17.91)  42.3 (19.52)   42.3 (19.75) Visit 7 (Day 98)/Stable Dose LOCF [1] n 6766 62 Mean (SD)   34.4 (17.01)   37.3 (18.74)   34.1 (17.85) Change fromBaseline (SD)  −4.3 (13.65)  −5.9 (14.76)  −8.3 (14.61) The analysisvisit window for Day 98 (Visit 7) for the primary endpoint used stabledose last observation carried forward (last data point collected afterDay 39 and before Day 102). n is the number of subjects with values ateach time point.

Table 20 presents the treatment comparisons of the Amantadine HCl ER 320mg group and the Amantadine HCl ER 240 mg group with placebo for meanchange in the sum of MDS-UPDRS Parts II and III from baseline to Day 98using stable dose LOCF for the Phase 3 ITT Population. No statisticallysignificant treatment differences were observed.

TABLE 20 Analysis of Mean Change in the Sum of MDS-UPDRS Parts II andIII from Baseline to Day 98 Using Stable Dose LOCF-Study A and StudyB-Phase 3 ITT Population Treatment Difference (Amantadine HCl ER vs.Placebo) 95% CI of Treatment Group LS Mean (SE) Difference DifferenceP-value Amantadine HCl ER 320 mg −5.3 (1.56) 2.7 (−1.8, 7.1) 0.235Amantadine HCl ER 240 mg −5.3 (1.57) 2.7 (−1.8, 7.1) 0.237 Placebo −7.9(1.62)

7.5.5.3 Change in Total UDysRS Score from Baseline to Day 42 and Day 70

Table 21 presents the results for mean change in Total UDysRS score frombaseline to Day 42 and Day 70 for the Phase 3 ITT Population. Frombaseline to Day 42 and Day 70, respectively, the mean reduction in theTotal UDysRS score was 14.0 and 14.8 for the Amantadine HCl ER 320 mggroup, 16.9 and 17.5 for the Amantadine HCl ER 240 mg group, and 8.2 and9.9 for the Placebo group. At both time points, there were largerreductions in the Total UDysRS score in the Amantadine HCl ER 320 mg andAmantadine HCl ER 240 mg groups compared with placebo.

TABLE 21 Mean Change in Total UDysRS Score from Baseline to Day 42 andDay 70-Study A and Study B-Phase 3 ITT Population Visit Amantadine HClER Amantadine HCl ER Statistic 320 mg 240 mg Placebo Visit 2 (Baseline)n 74 74 72 Mean (SD)   37.4 (12.21)   43.3 (13.74)   39.9 (12.94) Visit5 (Day 42) n 63 69 60 Mean (SD)   24.2 (13.01)   26.9 (14.16)   30.3(13.39) Change from Baseline (SD) −14.0 (11.03) −16.9 (14.59)  −8.2(11.25) Visit 6 (Day 70) n 58 55 54 Mean (SD)   22.4 (12.58)   25.6(14.12)   28.9 (14.16) Change from Baseline (SD) −14.8 (11.27) −17.5(14.45)  −9.9 (12.23) n is the number of subjects with values at eachtime point.

Table 22 presents the treatment comparisons of the Amantadine HCl ER 320mg group and the Amantadine HCl ER 240 mg group with placebo for meanchange in Total UDysRS score from baseline to Day 42 and Day 70 for theITT Population.

Treatment with Amantadine HCl ER 320 mg and 240 mg both resulted in asignificantly larger reduction in Total UDysRS score than placebo frombaseline to Day 42 and Day 70.

TABLE 22 Analysis of Mean Change in Total UDysRS Score from Baseline toDay 42 and Day 70—Study A and Study B—Phase 3 ITT Population TreatmentDifference (Amantadine HCl ER vs. Placebo) Visit LS Mean 95% CI ofP-value (Day) Treatment Group N (SE) Difference Difference versusPlacebo Visit 5 Amantadine HCl ER 63 −15.0 −6.4 (−10.2, −2.5) 0.001 (Day320 mg (1.37) 42) Amantadine HCl ER 69 −15.3 −6.6 (−10.5, −2.8) 0.001240 mg (1.33) Placebo 60  −8.6 (1.39) Visit 6 Amantadine HCl ER 58 −16.1−5.8 (−10.0, −1.6) 0.007 (Day 320 mg (1.49) 70) Amantadine HCl ER 55−16.2 −5.9 (−10.1, −1.6) 0.007 240 mg (1.50) Placebo 54 −10.3 (1.53) Amixed effect repeated measure analysis was performed on change frombaseline values with treatment group, visit, and treatmentgroup-by-visit interaction as fixed effects, patient as a random effectand baseline score as a covariate.

Overall Conclusions

The pooled results from two Phase 3 randomized, double-blind,placebo-controlled studies designed to evaluate the efficacy and safetyof Amantadine HCl ER Tablets with placebo in subjects with PD who hadLID were analyzed. The primary efficacy endpoint in these studies wasthe change from baseline to Day 98 in the Total UDysRS score. The pooledanalysis of these Phase 3 studies demonstrated that Amantadine HCl ERtablets, at both 320 mg and 240 mg administered once daily in themorning, improved dyskinesia in PD subjects with LID as determined bystatistically significant and clinically meaningful reductions in TotalUDysRS scores.

The Phase 3 studies enrolled male and female subjects 30 to 85 years ofage who had been diagnosed with idiopathic PD who had levodopa-inducedpredictable peak-effect dyskinesia considered by the subject to beproblematic and/or disabling. UDysRS and MDS-UPDRS were administeredwithin 3 hours of the last dose of levodopa to allow for consistentassessment of peak dose dyskinesia. The two Phase 3 studies randomized222 subjects: 75 subjects were randomized to Amantadine HCl ER 320 mg,75 subjects to Amantadine HCl ER 240 mg, and 72 subjects to placebo. Onehundred thirty-three subjects completed the respective studies.

Subjects recruited for the Phase 3 studies were typical of a populationwith PD who had LID. To enter the studies all subjects were required tobe currently treated with levodopa. The baseline mean dose of levodopawas 735 mg. For all subjects, the mean baseline Total UDysRS score was40. Across all treatment groups, the mean Hoehn & Yahr Stage was 2.

The primary analysis window was Day 98 (Visit 7) using stable dose LOCF,which included the last data point collected after Day 39 and before Day102. The LS mean reduction in Total UDysRS score was 14.7 for theAmantadine HCl ER 320 mg group, 15.1 for the Amantadine HCl ER 240 mggroup, and 9.5 for the Placebo group. From baseline to Day 98 withstable dose LOCF, treatment with Amantadine HCl ER 320 mg resulted in asignificantly larger reduction in Total UDysRS score than placebo (−5.2;p=0.017). Treatment with Amantadine HCl ER 240 mg also resulted in asignificantly larger reduction in Total UDysRS score than placebo (−5.5;p=0.012) from baseline to Day 98 with stable dose LOCF.

A key secondary endpoint in the Phase 3 trials was the change in thenumber of awake “ON” hours without troublesome dyskinesia from baselineto Day 98 using stable dose LOCF. Treatment with Amantadine HCl ER 320mg resulted in a larger increase in the number of awake “ON” hourswithout troublesome dyskinesia than placebo (2.3 hours; p<0.001).Treatment with Amantadine HCl ER 240 mg resulted in a mean increase inthe number of awake “ON” hours without troublesome dyskinesia, however,the treatment difference was not statistically significant compared withplacebo (1.0 hours; p=0.119).

MDS-UPDRS Part II and III was used to assess any potential worsening ofPD symptoms during the study. There was little change in the sum ofMDS-UPDRS Parts II and III compared with placebo at both dose levels ofAmantadine HCl ER, which suggests that treatment with Amantadine HCl ERdid not worsen PD symptoms.

In the analysis of the primary and secondary efficacy parameters bysubgroups, there were larger mean reductions in Total UDysRS scoreobserved in subjects who had more severe LID (baseline Total UDysRSscores>median) compared to subjects with less severe LID (baseline TotalUDysRS scores≤median). There were larger mean reductions in Total UDysRSobserved in the subgroup of subjects enrolled outside the US compared tothose subjects enrolled at sites in the US. There were no noteworthytrends in mean change in Total UDysRS scores or in mean change in awake“ON” hours without troublesome dyskinesia from baseline to Day 98 usingstable dose LOCF based on subpopulations of age, race, gender, orbaseline levodopa dose categories (≤median vs.>median dose).

In the pooled efficacy analysis from Study A and Study B, treatment withAmantadine HCl ER 320-mg and 240-mg tablets for 12 weeks was effectivein improving dyskinesia in PD subjects with LID as measured by objectiveand subjective measures. Both doses produced statistically significantreductions in Total UDysRS score, and Amantadine HCl ER 320 mg wasassociated with a statistically significant increase in awake “ON” hourswithout troublesome dyskinesia.

Example 8 Safety

The safety of Amantadine ER tablets, prepared according to Example 1,was evaluated in two placebo-controlled clinical studies in the U.S.,Canada, and Europe. Adverse events were consistent and no new orunexpected safety issues were reported. Throughout the study, the mostfrequently reported Treatment-emergent adverse events (TEAEs) bypreferred term were hallucinations (8.1%), increased dyskinesia (8.1%),fall (7.2%), nausea (7.2%), dry mouth (5.4%), peripheral edema (5.0%),urinary tract infection (5.0%), and somnolence (5.0%).

Example 9 Clinical Trials on Patients with Drug-Induced ExtrapyramidalReactions

A clinical trial on the effects of amantadine on drug-inducedextrapyramidal reactions is conducted. Inclusion criteria includepatients, both male and female, who are 18 years old of age and olderand who suffer from drug-induced extrapyramidal reactions. The patientsexhibit at least one of the following symptoms: dystonia (continuousspasms and muscle contractions), akathisia (motor restlessness),parkinsonism (characteristic symptoms such as rigidity), bradykinesia(slowness of movement), tremor, and tardive dyskinesia (irregular, jerkymovements).

Studies are conducted to evaluate the efficacy and safety of AmantadineHCl ER Tablets at dosages of 160 mg/day, 240 mg/day and 320 mg/day forthe treatment of patients with drug-induced extrapyramidal reactions.

Study C and D

These two studies are two fixed-dose trials (after a Titration Period)that compare the efficacy and safety of Amantadine HCl ER tablets withplacebo in subjects 18 to 85 years of age with drug-inducedextrapyramidal reactions. Eligible subjects are randomized in a 1:1:1:1manner into one of four treatment groups: Amantadine HCl ER 320 mg,Amantadine HCl ER 240 mg, Amantadine HCl ER 160 mg, or Placebo.

Subjects assigned to the Amantadine HCl ER 320 mg group undergo a 2-weekdose titration beginning with a 160 mg QD dose for 1 week, then a 240 mgQD dose for 1 week, and then a 320 mg QD dose for 12 weeks or 22 weeksfollowed by a dose-taper for 2 weeks. Subjects assigned to theAmantadine HCl ER 240 mg group undergo a 2-week dose titration beginningwith placebo QD dose for 1 week, then a 160 mg QD dose for 1 week, andthen a 240 mg QD dose for 12 weeks or 22 weeks followed by a dose-taperfor 2 weeks. Subjects assigned to the Amantadine HCl ER 160 mg groupbegin with placebo QD dose for 1 week, and then a 160 mg QD dose for 15weeks or 25 weeks. Subjects assigned to the Placebo group take placebotablets QD for 16 weeks or 26 weeks.

During the Titration Period, patients randomized to the Amantadine ER240 mg treatment group receive placebo daily for one week, thenAmantadine ER 160 mg daily for one week, before increasing to the 240 mgonce daily maintenance dose. Patients in the Amantadine ER 320 mgtreatment group receive Amantadine ER 160 mg daily for one week, thenAmantadine ER 240 mg daily for one week, before increasing to the 320 mgonce daily maintenance dose. The 2-week dose controlled Taper Periodfollows the 12-week and 26-week Maintenance Periods, respectively.During the Taper Period, patients receiving Amantadine ER 240 mg dailyare withdrawn from study medication by receiving Amantadine ER 160 mgdaily for 1 week, then placebo for 1 week. Patients receiving AmantadineER 320 mg daily are withdrawn from study medication by receivingAmantadine ER 240 mg daily for 1 week, then Amantadine ER 160 mg for 1week.

Study C and Study D are almost identical; the primary difference betweenthe two studies is the duration of treatment. The duration of treatmentis 16 and 26 weeks for Study C and Study D, respectively.

For efficacy assessments, the patients are assessed with the followingrating scales that are commonly used to assess the severity of movementdisorders: Simpson-Angus Scale (SAS), Barnes Akathisia Rating Scale(BARS), Abnormal Involuntary Movement Scale (AIMS), and ExtrapyramidalSymptom Rating Scale (ESRS).

1-30. (canceled)
 31. A method of treating a drug-induced extrapyramidalreaction in an adult patient, comprising: i) administering to thepatient once daily in the morning a pharmaceutical compositioncomprising about 129 mg of amantadine free base equivalent for about oneweek; ii) increasing the dose of amantadine by administering to thepatient once daily in the morning a pharmaceutical compositioncomprising about 193 mg of amantadine free base equivalent; wherein eachof the pharmaceutical compositions comprises i) an extended releasecomponent comprising amantadine free base equivalent; and ii) animmediate release component comprising about 48 mg of amantadine freebase equivalent; wherein each of the pharmaceutical compositions is asolid oral dosage form, wherein the maximum daily dose of amantadine isabout 322 mg of amantadine free base equivalent, wherein the meanC_(max) of the pharmaceutical composition comprising about 129 mg ofamantadine free base equivalent after a single-dose administration isbetween about 50% and about 125% of the mean C_(max) provided by thesame quantity of amantadine or a pharmaceutically acceptable saltthereof in an immediate release form; and wherein the mean C_(max) ofthe pharmaceutical composition comprising about 193 mg of amantadinefree base equivalent after a single-dose administration is between about50% and about 175% of the mean C_(max) provided by the same quantity ofamantadine or a pharmaceutically acceptable salt thereof in an immediaterelease form.
 32. The method of claim 31, wherein the mean C_(max) ofthe pharmaceutical composition comprising about 129 mg of amantadinefree base equivalent after a single-dose administration is between about75% and about 100% of the mean C_(max) provided by the same quantity ofamantadine or a pharmaceutically acceptable salt thereof in an immediaterelease form.
 33. The method of claim 31, wherein the mean C_(max) ofthe pharmaceutical composition comprising about 129 mg of amantadinefree base equivalent after a single-dose administration is between about200 and about 500 ng/mL.
 34. The method of claim 33, wherein the meanC_(max) of the pharmaceutical composition comprising about 129 mg ofamantadine free base equivalent after a single-dose administration isbetween about 265 and about 390 ng/mL.
 35. The method of claim 31,wherein the mean C_(max) of the pharmaceutical composition comprisingabout 193 mg of amantadine free base equivalent after a single-doseadministration is between about 100% and about 125% of the mean C_(max)provided by the same quantity of amantadine or a pharmaceuticallyacceptable salt thereof in an immediate release form.
 36. The method ofclaim 31, wherein the mean C_(max) of the pharmaceutical compositioncomprising about 193 mg of amantadine free base equivalent after asingle-dose administration is between about 200 and about 700 ng/mL. 37.The method of claim 36, wherein the mean C_(max) of the pharmaceuticalcomposition comprising about 193 mg of amantadine free base equivalentafter a single-dose administration is between about 370 and about 550ng/mL.
 38. A method of treating a drug-induced extrapyramidal reactionin an adult patient, comprising: i) administering to the patient oncedaily in the morning a pharmaceutical composition comprising about 129mg of amantadine free base equivalent for about one week; ii) increasingthe dose of amantadine by administering to the patient once daily in themorning a pharmaceutical composition comprising about 193 mg ofamantadine free base equivalent; wherein each of the pharmaceuticalcompositions comprises i) an extended release component comprisingamantadine free base equivalent; and ii) an immediate release componentcomprising about 48 mg of amantadine free base equivalent, wherein eachof the pharmaceutical compositions is a solid oral dosage form, whereinthe maximum daily dose of amantadine is about 322 mg of amantadine freebase equivalent, wherein the mean AUC_(0-∞) of the pharmaceuticalcomposition comprising about 129 mg of amantadine free base equivalentafter a single-dose administration is between 65% and about 135% of themean AUC_(0-∞) provided by the same quantity of amantadine or apharmaceutically acceptable salt thereof in an immediate release form,and wherein the mean AUC_(0-∞) of the pharmaceutical compositioncomprising about 193 mg of amantadine free base equivalent after asingle-dose administration is between 85% and about 225% of the meanAUC_(0-∞) provided by the same quantity of amantadine or apharmaceutically acceptable salt thereof in an immediate release form.39. The method of claim 38, wherein the mean AUC_(0-∞) of thepharmaceutical composition comprising about 129 mg of amantadine freebase equivalent after a single-dose administration is between about 90%and about 110% of the mean AUC_(0-∞) provided by the same quantity ofamantadine or a pharmaceutically acceptable salt thereof in an immediaterelease form.
 40. The method of claim 38, wherein the mean AUC_(0-∞) ofthe pharmaceutical composition comprising about 129 mg of amantadinefree base equivalent after a single-dose administration is between about6,000 and about 12,000 ng·h/mL.
 41. The method of claim 38, wherein themean AUC_(0-∞) of the pharmaceutical composition comprising about 193 mgof amantadine free base equivalent after a single-dose administration isbetween about 130% and about 180% of the mean AUC_(0-∞) provided by thesame quantity of amantadine or a pharmaceutically acceptable saltthereof in an immediate release form.
 42. The method of claim 38,wherein the mean AUC_(0-∞) of the pharmaceutical composition comprisingabout 193 mg of amantadine free base equivalent after a single-doseadministration is between about 8,000 and about 20,000 ng·h/mL.
 43. Amethod of treating a drug-induced extrapyramidal reaction in an adultpatient, comprising: i) administering to the patient once daily in themorning a pharmaceutical composition comprising about 129 mg ofamantadine free base equivalent for about one week; ii) increasing thedose of amantadine by administering to the patient once daily in themorning a pharmaceutical composition comprising about 193 mg ofamantadine free base equivalent for at least one week; iii) increasingthe dose of amantadine by administering to the patient once daily in themorning a pharmaceutical composition comprising about 258 mg ofamantadine free base equivalent; wherein each of the pharmaceuticalcompositions comprises i) an extended release component comprisingamantadine free base equivalent; and ii) an immediate release componentcomprising about 48 mg of amantadine free base equivalent, wherein eachof the pharmaceutical compositions is a solid oral dosage form, whereinthe maximum daily dose of amantadine is about 322 mg of amantadine freebase equivalent, wherein the mean C_(max) of the pharmaceuticalcomposition comprising about 129 mg of amantadine free base equivalentafter a single-dose administration is between about 50% and about 125%of the mean C_(max) provided by the same quantity of amantadine or apharmaceutically acceptable salt thereof in an immediate release form,wherein the mean C_(max) of the pharmaceutical composition comprisingabout 193 mg of amantadine free base equivalent after a single-doseadministration is between about 50% and about 175% of the mean C_(max)provided by the same quantity of amantadine or a pharmaceuticallyacceptable salt thereof in an immediate release form, and wherein themean C_(max) of the pharmaceutical composition comprising about 258 mgof amantadine free base equivalent after a single-dose administration isbetween about 95% and about 250% of the mean C_(max) provided by thesame quantity of amantadine or a pharmaceutically acceptable saltthereof in an immediate release form.
 44. The method of claim 43,wherein the mean C_(max) of the pharmaceutical composition comprisingabout 129 mg of amantadine free base equivalent after a single-doseadministration is between about 75% and about 100% of the mean C_(max)provided by the same quantity of amantadine or a pharmaceuticallyacceptable salt thereof in an immediate release form.
 45. The method ofclaim 43, wherein the mean C_(max) of the pharmaceutical compositioncomprising about 129 mg of amantadine free base equivalent after asingle-dose administration is between about 200 and about 500 ng/mL. 46.The method of claim 45, wherein the mean C_(max) of the pharmaceuticalcomposition comprising about 129 mg of amantadine free base equivalentafter a single-dose administration is between about 265 and about 390ng/mL.
 47. The method of claim 43, wherein the mean C_(max) of thepharmaceutical composition comprising about 193 mg of amantadine freebase equivalent after a single-dose administration is between about 100%and about 125% of the mean C_(max) provided by the same quantity ofamantadine or a pharmaceutically acceptable salt thereof in an immediaterelease form.
 48. The method of claim 43, wherein the mean C_(max) ofthe pharmaceutical composition comprising about 193 mg of amantadinefree base equivalent after a single-dose administration is between about200 and about 700 ng/mL.
 49. The method of claim 48, wherein the meanC_(max) of the pharmaceutical composition comprising about 193 mg ofamantadine free base equivalent after a single-dose administration isbetween about 370 and about 550 ng/mL.
 50. The method of claim 43,wherein the mean C_(max) of the pharmaceutical composition comprisingabout 258 mg of amantadine free base equivalent after a single-doseadministration is between about 150% and about 175% of the mean C_(max)provided by the same quantity of amantadine or a pharmaceuticallyacceptable salt thereof in an immediate release form.
 51. The method ofclaim 43, wherein the mean C_(max) of the pharmaceutical compositioncomprising about 258 mg of amantadine free base equivalent after asingle-dose administration is between about 400 and about 1,000 ng/mL.52. The method of claim 51, wherein the mean C_(max) of thepharmaceutical composition comprising about 258 mg of amantadine freebase equivalent after a single-dose administration is between about 540and about 895 ng/mL.
 53. A method of treating a drug-inducedextrapyramidal reaction in an adult patient, comprising: i)administering to the patient once daily in the morning a pharmaceuticalcomposition comprising about 129 mg of amantadine free base equivalentfor about one week; ii) increasing the dose of amantadine byadministering to the patient once daily in the morning a pharmaceuticalcomposition comprising about 193 mg of amantadine free base equivalentfor at least one week; iii) increasing the dose of amantadine byadministering to the patient once daily in the morning a pharmaceuticalcomposition comprising about 258 mg of amantadine free base equivalent;wherein each of the pharmaceutical compositions comprises i) an extendedrelease component comprising amantadine free base equivalent; and ii) animmediate release component comprising about 48 mg of amantadine freebase equivalent, wherein each of the pharmaceutical compositions is asolid oral dosage form, wherein the maximum daily dose of amantadine isabout 322 mg of amantadine free base equivalent, wherein the meanAUC_(0-∞) of the pharmaceutical composition comprising about 129 mg ofamantadine free base equivalent after a single-dose administration isbetween 65% and about 135% the mean AUC_(0-∞) provided by the samequantity of amantadine or a pharmaceutically acceptable salt thereof inan immediate release form, wherein the mean AUC_(0-∞) of thepharmaceutical composition comprising about 193 mg of amantadine freebase equivalent after a single-dose administration is between 85% andabout 225% the mean AUC_(0-∞) provided by the same quantity ofamantadine or a pharmaceutically acceptable salt thereof in an immediaterelease form, and wherein the mean AUC_(0-∞) of the pharmaceuticalcomposition comprising about 258 mg of amantadine free base equivalentafter a single-dose administration is between about 130% and about 290%of the mean AUC_(0-∞) provided by the same quantity of amantadine or apharmaceutically acceptable salt thereof in an immediate release form.54. The method of claim 53, wherein the mean AUC_(0-∞) of thepharmaceutical composition comprising about 129 mg of amantadine freebase equivalent after a single-dose administration is between about 90%and about 110% of the mean AUC_(0-∞) provided by the same quantity ofamantadine or a pharmaceutically acceptable salt thereof in an immediaterelease form.
 55. The method of claim 53, wherein the mean AUC_(0-∞) ofthe pharmaceutical composition comprising about 129 mg of amantadinefree base equivalent after a single-dose administration is between about6,000 and about 12,000 ng·h/mL.
 56. The method of claim 53 wherein themean AUC_(0-∞) of the pharmaceutical composition comprising about 193 mgof amantadine free base equivalent after a single-dose administration isbetween about 130% and about 180% of the mean AUC_(0-∞) provided by thesame quantity of amantadine or a pharmaceutically acceptable saltthereof in an immediate release form.
 57. The method of claim 53,wherein the mean AUC_(0-∞) of the pharmaceutical composition comprisingabout 193 mg of amantadine free base equivalent after a single-doseadministration is between about 8,000 and about 20,000 ng·h/mL.
 58. Themethod of claim 53, wherein the mean AUC_(0-∞) of the pharmaceuticalcomposition comprising about 258 mg of amantadine free base equivalentafter a single-dose administration is between about 175% and about 225%of the mean AUC_(0-∞) provided by the same quantity of amantadine or apharmaceutically acceptable salt thereof in an immediate release form.59. The method of claim 53, wherein the mean AUC_(0-∞) of thepharmaceutical composition comprising about 258 mg of amantadine freebase equivalent after a single-dose administration is between about12,000 and about 26,000 ng·h/mL.